Collections: Fortification, Part IV: French Guns and Italian Lines

This is the fourth part of a five part (I, II, III) series covering some of the basics of fortification, from city walls to field fortifications, from the ancient world to the modern period. Last week, we set out an overview of fortifications in medieval Europe, with particular focus on the strategic role of castles and point defenses.

This week, we’re going to look at the impact artillery has on these systems. So far the fortifications we have been looking at have mostly been designed to resist escalade – enemies coming over the walls, by whatever means. Indeed, on the ‘list of threats’ medieval and ancient fortifications were clearly more concerned about escalade, treachery and starvation; breaching was clearly a secondary concern, with some design implications we’ll talk about here shortly. That was a sensible set of priorities because, as we’ll see, until the development of mature gunpowder artillery in the mid-15th century, artillery (by which we mean catapults), while they existed and could be very useful in a siege, were not generally up to the task of actually breaching a castle’s curtain wall.

Gunpowder decisively changes that and as a result transforms fortifications, though as we’ll see, it doesn’t do so uniformly either in design or geographically.

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Bibliography Note! As we’ve discussed in the past, trace italienne fortresses (the sort we’re going to talk about here) sit at the center of the debate over the ‘military revolution’ – the source of the sudden increase in military capacity tied to gunpowder in Europe from about 1450 to about 1750. Consequently, there is a lot of bibliography on them. This post owes its data to several key works, namely, T. Andrade, The Gunpowder Age: China, Military Innovation and the Rise of the West in World History (2016), G. Parker, The Military Revolution: Military Innovation and the Rise of the West 1500-1800 (1988; 2nd ed. 1996), and G. Parker, The Army of Flanders and the Spanish Road, 1567-1659 (1972; 2nd ed. 2004). There’s a lot more on this, but that’s a good place to start. Since we’re also discussing catapults, I should note that the standard work on Greek and Roman catapults remains E.W. Marsden, Greek and Roman Artillery: Historical Developments (1969), while the most recent monograph discussion of medieval European catapults that I know of is M. Fulton, Artillery in the Era of the Crusades: Siege Warfare and the Development of Trebuchet Technology (2018); alas, neither book is particularly affordable, so see if you can’t get your library to swing you a copy (Marsden, in particular, is difficult to find; note that it comes in two volumes – you want Historical Developments, rather than Technical Treatises). There is a decent discussion of the use of catapults in sieges in C. Rogers, Soldiers’ Lives Through History: The Middle Ages (2007), 121-4. Towards the end, we briefly touch on the question of firepower in the American Civil War. The key reading here is E.J. Hess, The Rifle Musket in Civil War Combat: Reality and Myth (2008) and E.J. Hess, Field Armies and Fortifications in the Civil War: The Eastern Campaign 1861-1864 (2005), but note also B. Gibbons, The Destroying Angel: The Rifle-Musket as the First Modern Infantry Weapon (2019). Finally, for a fairly approachable overview of the changing nature of warfare in this period, see Lee, Waging War: Conflict, Culture and Innovation in World History (2016), ch. 7-11.

Catapults (…Aren’t in Chess, So They Go Here)

Cannon weren’t the first form of artillery used to batter fortifications, so before we get to gunpowder it is worth backing up and discussing catapults and the sort of ‘artillery threat’ that catapults create. And here once again we need to clarify some terms: catapults are generally defined by the mechanism they use to store and then release energy, because that is fundamentally what a catapult is: a device for storing up some energy and then releasing it very suddenly to propel a large object.

The very oldest catapults, first invented by the Greeks were tension catapults (the gastrophetes and oxybeles), which functioned like large bows, with a bow-staff being bent backwards to store and then release the launching energy. This sort of design, common in pop-cultural depictions of catapults, is actually quite limited as with the materials available, there is a real limit to how much energy can be stored via tension. Fortunately for the Greeks, by the early fourth century, they had developed a better method.

Instead, the Greeks, Macedonians and Romans began using torsion catapults (where the energy is stored in wound-up sinews like a spring). While the devices used in field battles (and for city defense) were often smaller, arrow-launching devices, siege catapults could be very large; the standard engine for the purpose could fling a 1 talent stone (26.2kg) about 400m (though effectiveness was far higher if you could get closer to the wall, which as we’ll see will be a trend for most of this post); much larger engines did exist as well. That said, Roman catapults were mostly not for collapsing walls but for destroying towers and suppressing defenders in order to aid in escalade (usually by mole, rather than ladders or towers, though the Romans used those too).

Via Wikipedia, a selection of small reconstructed Greek and Roman catapults from Saalburg. Roman siege catapults came much larger than this

And here once again the distinction between the ‘big army siege package’ and the ‘small army siege package’ matters quite a bit. Roman torsion artillery was complex, expensive and required lots of technical skill, and so sees far diminished use in the early Middle Ages where that technical skill is hard to come by. Vespasian, we are told, brought 160 torsion catapults to besiege Jotapata in 67 (Josephus BJ 3.166) while Titus brings a stunning 340 to besiege Jerusalem in 70 (Josephus BJ 5.356). By contrast, the construction of a single catapult is often a major event in a medieval siege (see Rogers, op. cit. 121-3 for some examples) and while later medieval catapults were often more powerful than the earlier Roman torsion devices, they were not that much more powerful.

Consequently, Hellenistic and Roman fortifications (especially city walls, like the Theodosian Walls we discussed last time) were designed with massed catapults in mind. As noted, the multiple walls ensured that the main curtain wall, the inner wall, was extremely difficult to target with catapults or indeed any kind of artillery: even if you knocked down the low wall and the outer wall, their rubble would mostly block shots at the base of the inner wall. Meanwhile, the inner wall was built to be practically immune to catapult fire anyway: up to 6m thick without any internal passages (the outer wall was much thinner, only 2m). That was more than enough to render the walls effectively immune to anything catapults can do; the walls in many places still stood up to Ottoman cannon in 1453. Finally, ancient city defenses were built assuming they’d often have their own stone and arrow throwing torsion artillery set up on the towers to return ‘counter-battery’ fire. Not every city had the ‘complete package’ that Constantinople, as the imperial capital head, of course, but some mix of thick walls, low out-walls and catapults designed for counter-battery fire were fairly standard defensive arrangements for Roman cities that could afford them and felt sufficiently threatened to invest the resources.

As we move into the Middle Ages, two paradoxical things happen. On the one hand, the ability for societies in Europe to deploy large numbers of finicky, high-tech torsion artillery decreases dramatically (and the machines that we do see tend to be the simpler, less accurate single-armed variety, what the Romans called the onager or ‘wild ass’ because it kicked like one when it fired). On the other hand, by the sixth century, we start to see a clever new design of catapult, the traction trebuchet.

Originating in China in the 4th century BC, the traction catapult used muscle power directly to swing a long pole around a central frame. In terms of engineering complexity, it was a simpler device, and could be scaled up quite large so long as one could add more pullers (around 100 seems to have been normal for a large engine), but the range and power it offered as a result of the mechanical advantage offered by the long throwing arm were considerable. Given the number of pullers required, it is little surprise these were generally only used in small numbers in medieval Europe (again, often in reports it is merely a single device, described as a mangonel or a fenevol), but on the other hand, as I understand the physics, the range and striking power had the potential to be superior to a torsion catapult. Nevertheless, if we look at the kinds of fortifications emerging during this period, it certainly seems like in Europe, the concern that artillery might produce a breach in the wall (as opposed to merely degrading towers and the wall-walk) was fairly low.

Via Wikipedia, a 12th century manuscript illustration showing the use of a traction trebuchet (note the ropes handing down from the short end of the rod for pulling on.

Just to throw down a note here because we’ll come back to it, it is striking that while the small numbers of traction trebuchets in Europe seem to have represented a decline in the ‘catapult threat’ to walls (recall last week’s contrast between castle walls and the much older Theodosian Walls), that was not the case in China, where walls continued to be made very thick – a design quirk that will matter quite a lot in a moment. I am not an expert on ancient and medieval Chinese siege tactics, alas, but my brief encounters with accounts of them often seem to describe traction catapults used en masse, in dozens or even hundreds, much more the way that the Romans used massed siege artillery. Likewise, Michael Fulton (Artillery in the Era of the Crusades (2018)) notes nearly a hundred Mamluk trebuchets (a mix of counter-weight and traction) at the Siege of Acre (1291); my sense is that such large siege trains were very rare within Europe. Presumably the ability to deploy so many engines was a consequence of greater state capacity in China and the Near East during this period as compared to fragmented, decentralized medieval Europe.

The late 12th century sees a major variation on the trebuchet design: the use of a counter-weight, instead of traction to provide the force; this innovation seems to have emerged in the West broadly defined, though it isn’t clear if that means in Europe or the Middle East (in any event both Christian and Muslim armies start using them at almost exactly the same time). This allows for much more energy to put into the shot, as the counter-weight can be very heavy and only slowly winched into place, allowing the work crew to spend more time ‘storing’ energy in the counter-weight than they could with the quick pull of a traction trebuchet. Larger counter-weight trebuchets could also make use of animals to provide the power, or large wheels to make it easier to raise the counter-weight. The upper-limits on the size of projectiles were very high: Warwolf is thought to be the largest such trebuchet known, and threw a nearly 300lbs shot. That said, while counter-weight trebuchets hit harder (but fired slower), in function they do not seem to have been meaningfully different from traction trebuchets; they were used the same way in sieges.

Via Wikipedia, a diagram of a large counterweight trebuchet.

What’s really striking is not the vast impact of catapults, but the muted impact of catapults. The counter-weight trebuchet was clearly good: the innovation makes its way all the way back to China, carried by the Mongols who presumably picked it up in the Middle East (ironically moving the opposite direction but at the same time as gunpowder, suggesting that at this point in the 13th century the two technologies were not considered mutually exclusive). Castle design does respond to catapults, but only in relatively modest ways: walls get somewhat thicker, but as Fulton (op cit.) notes, only by about half a meter or so (leaving even the newly thickened medieval castle walls somewhat thinner than the best old Roman defenses). In at least some areas, towers and keeps become more frequently rounded in shape, to resist catapult fire.

Certainly it was possible for catapults to open breaches in weaker walls to enable assault. The aforementioned Warwolf opened large breaches in the stone walls of Stirling Castle in 1304. But I note both Rogers (op. cit.) and Fulton (op. cit.) seem to confirm that while true breaches from trebuchets could happen, it was far more common that walls resisted trebuchet strikes and that the real work of the machines was degrading the wall defenses by striking off battlements and smashing towers, in order to enable escalade. Which is little surprise: that’s precisely what the Romans used catapults for too. While there is still some argument about the degree to which the counter-weight trebuchet was a revolutionary military technology, on the balance, the siege playbook changed only modestly to accommodate it, and castle design likewise shifted only in degrees.

And then Charles VIII of France (r. 1483-1498) decided to take a holiday on the Bay of Naples.

Chuck’s Italian Vacation

Of course that last line is a click-bait oversimplification. In fact what we should say here is that the basic formula for what would become gunpowder (saltpeter, charcoal and sulfur in a roughly 75%, 15%, 10% mixture) was clearly in use in China by 1040 when we have our first attested formula, though saltpeter had been being refined and used as an incendiary since at least 808. The first guns appear to be extrapolations from Chinese incendiary ‘fire lances’ (just add rocks!) and the first Chinese cannon appear in 1128. Guns arrive in Europe around 1300; our first representation of a cannon is from 1326, while we hear about them used in sieges beginning in the 1330s; the Mongol conquest and the sudden unification of the Eurasian Steppe probably provided the route for gunpowder and guns to move from China to Europe. Notably, guns seem to have arrived as a complete technology: chemistry, ignition system, tube and projectile.

There was still a long ‘shaking out’ period for the new technology: figuring out how to get enough saltpeter for gunpowder (now that’s a story we’ll come back to some day), how to build a large enough and strong enough metal barrel, and how to actually use the weapons (in sieges? against infantry? big guns? little guns?) and so on. By 1453, the Ottomans have a capable siege-train of gunpowder artillery. Mehmed II (r. 1444-1481) pummeled the walls of Constantinople with some 5,000 shots using some 55,000 pounds of gunpowder; at last Theodosius’ engineers had met their match.

Via Wikipedia, Mons Meg, a large hoop-and-stave constructed cannon built in Burgundy in 1449 and sent to Scotland in 1454.

And then, in 1494, Charles VIII invaded Italy – in a dispute over the throne of Naples – with the first proper mobile siege train in Christendom (not in Europe, mind you, because Mehmed had beat our boy Chuck here by a solid four decades). A lot of changes had been happening to make these guns more effective: longer barrels allowed for more power and accuracy, wheeled carriages made them more mobile, trunnions made elevation control easier and some limited degree of caliber standardization reduced windage and simplified supply (though standardization at this point remains quite limited).

The various Italian states, exactly none of whom were excited to see Charles attempting to claim the Kingdom of Naples, could have figured that the many castles and fortified cities of northern Italy were likely to slow Charles down, giving them plenty of time to finish up their own holidays before this obnoxious French tourist showed up. On the 19th of October, 1494, Charles showed up to besiege the fortress at Mordano – fortress which might well have been expected to hold him up for weeks or even months; on October 20th, 1494, Charles sacked Mordano and massacred the inhabitants, after having blasted a breach with his guns. Florence promptly surrendered and Charles marched to Naples, taking it in 1495 (it surrendered too). Francesco Guicciardini phrased it thusly (trans. via Lee, Waging War, 228),

They [Charles’ artillery] were planted against the Walls of a Town with such speed, the Space between the Shots was so little, and the Balls flew so quick, and were impelled with such Force, that as much Execution was done in a few Hours, as formerly, in Italy, in the like Number of Days.

The impacts of the sudden apparent obsolescence of European castles were considerable. The period from 1450 to 1550 sees a remarkable degree of state-consolidation in Europe (broadly construed)1 castles, and the power they gave the local nobility to resist the crown, had been one of the drivers of European fragmentation, though we should be careful not to overstate the gunpowder impact here: there are a other reasons for a burst of state consolidation at this juncture. Of course that creates a run-away effect of its own, as states that consolidate have the resources to employ larger and more effective siege trains.

Now this strong reaction doesn’t happen everywhere or really anywhere outside of Europe. part of that has to do with the way that castles were built. Because castles were designed to resist escalade, the walls needed to be built as high as possible, since that was the best way to resist attacks by ladders or towers. But of course, given a fixed amount of building resources, building high also means building thin (and European masonry techniques enabled tall-and-thin construction with walls essentially being constructed with a thick layer of fill material sandwiched between courses of stone). But ‘tall and thin,’ while good against ladders, was a huge liability against cannon.

By contrast, city walls in China were often constructed using a rammed earth core. In essence, earth was piled up in courses and packed very tightly, and then sheathed in stone. This was a labor-intensive building style (but large cities and lots of state capacity meant that labor was available), and it meant the walls had to be made thick in order to be made tall since even rammed earth can only be piled up at an angle substantially less than vertical. But against cannon, the result was walls which were already massively thick, impossible to topple over and the earth-fill, unlike European stone-fill, could absorb some of the energy of the impact without cracking or shattering. Even if the stone shell was broken, the earth wouldn’t tumble out (because it was rammed), but would instead self-seal small gaps. And no attacker could hope that a few lucky hits to the base of a wall built like this would cause it to topple over, given how wide it is at the base. Consequently, European castle walls were vulnerable to cannon in a way that contemporary walls in many other places, such as China, were not. Again, path dependence in fortification matters, because of that antagonistic co-evolution.

Via Wikipedia, an image of a defensive wall in Xi’an, which has been cut through so you can see the interior. You could shoot cannon at this all day and not get very far: breaching this would take a long time.

In the event, in Italy, Charles’ Italian Vacation started to go badly almost immediately after Naples was taken. A united front against him, the League of Venice, formed in 1495 and fought Charles to a bloody draw at Fornovo in July, 1495. In the long-term, French involvement would draw in the Habsburgs, whose involvement would prevent the French from making permanent gains in a series of wars in Italy lasting well into the 1550s.

But more relevant for our topic was the tremendous shock of that first campaign and the sudden failure of defenses which had long been considered strong. The reader can, I’d argue, detect the continued light tremors of that shock as late as Machiavelli’s The Prince (1532, but perhaps written in some form by 1513). Meanwhile, Italian fortress designers were already at work retrofitting old castles and fortifications (and building new ones) to more effectively resist artillery. Their secret weapon? Geometry.

Math Fort

Now I should note that the initial response in Italy to the shocking appearance of effective siege artillery was not to immediately devise an almost entirely new system of fortifications from first principles, but rather – as you might imagine – to hastily retrofit old fortresses. But for the sake of keeping complication in what is already bound to be a long post reasonably limited, we’re going to focus on the eventual new system of fortresses which emerge, with the first mature examples appearing around the first decades of the 1500s in Italy. This system of European gunpowder fort that spreads throughout much of Europe and into the by-this-point expanding European imperial holdings abroad (albeit more unevenly there) goes by a few names: ‘bastion’ fort (functional, for reasons we’ll get to in a moment), ‘star fort’ (marvelously descriptive), and the trace italienne or ‘the Italian line.’ since that was where it was from.

Since the goal remains preventing an enemy from entering a place, be that a city or a fortress, the first step has to be to develop a wall that can’t simply be demolished by artillery in a good afternoon or two. The solution that is come upon ends up looking a lot like those Chinese rammed earth walls: earthworks are very good at absorbing the impact of cannon balls (which, remember, are at this point just that: stone and metal balls; they do not explode yet): small air pockets absorb some of the energy of impact and dirt doesn’t shatter, it just displaces (and not very far: again, no high explosive shells, so nothing to blow up the earthwork). Facing an earthwork mound with stonework lets the earth absorb the impacts while giving your wall a good, climb-resistant face.

So you have your form: a stonework or brick-faced wall that is backed up by essentially a thick earthen berm like the Roman agger. Now you want to make sure incoming cannon balls aren’t striking it dead on: you want to literally play the angles. Inclining the wall slightly makes its construction easier and the end result more stable (because earthworks tend not to stand straight up; note the rammed-earth core wall pictured above and how its sides angle) and gives you an non-perpendicular angle of impact from cannon when they’re firing at very short range (and thus at very low trajectory), which is when they are most dangerous since that’s when they’ll have the most energy in impact. Ideally, you’ll want more angles than this, but we’ll get to that in a moment.

Because we now have a problem: escalade. Remember escalade?

Crap, he’s back. Just don’t make eye contact, and he’ll go away.
I am going to keep making this joke until one of you laughs. I am not proud. Or tired.

Earthworks need to be wide at the base to support a meaningful amount of height, tall-and-thin isn’t an option. Which means that in building these cannon resistant walls, for a given amount of labor and resources and a given wall circuit, we’re going to end up with substantially lower walls. We can enhance their relative height with a ditch or several out in front (and we will), but that doesn’t change the fact that our walls are lower and also that they now incline backwards slightly, which makes them easier to scale or get ladders on. But obviously we can’t achieved much if we’ve rendered our walls save from bombardment only to have them taken by escalade. We need some way to stop people just climbing over the wall.

The solution here is firepower. Whereas a castle was designed under the assumption the enemy would reach the foot of the wall (and then have their escalade defeated), if our defenders can develop enough fire, both against approaching enemies and also against any enemy that reaches the wall, they can prohibit escalade. And good news: gunpowder has, by this point, delivered much more lethal anti-personnel weapons, in the form of lighter cannon but also in the form of muskets and arquebuses. At close range, those weapons were powerful enough to defeat any shield or armor a man could carry, meaning that enemies at close range trying to approach the wall, set up ladders and scale would be extremely vulnerable: in practice, if you could get enough muskets and small cannon firing at them, they wouldn’t even be able to make the attempt.

Via Wikipedia, a bastion (the ‘home plate’ shaped hollow pentagram) at the fortress of Komárno, Slovakia.

But the old projecting tower of the castle, you will recall, was designed to allow only a handful of defenders fire down any given section of wall; we still want that good enfilade fire effect, but we need a lot more space to get enough muskets up there to develop that fire. The solution: the bastion. A bastion was an often diamond or triangular-shaped projection from the wall of the fort, which provided a longer stretch of protected wall which could fire down the length of the curtain wall. It consists of two ‘flanks’ which meet the curtain wall and are perpendicular to it, allowing fire along the wall; the ‘faces’ (also two) then face outward, away from the fort to direct fire at distant besiegers. When places at the corners of forts, this setup tends to produce outward-spiked diamonds, while a bastion set along a flat face of curtain wall tends to resemble an irregular pentagon (‘home plate’) shape. The added benefit for these angles? From the enemy siege lines, they present an oblique profile to enemy artillery, making the bastions quite hard to batter down with cannon, since shots will tend to ricochet off of the slanted line.

Via Wikipedia, the Castillo de San Marcos in Florida, a fairly simple bastion fort with four bastions. The base of each diamond (closest to the curtain) allows for firing directly along the base of the curtain, while the longer tip provides positions for muskets or cannon (mostly the latter) to be directed outward against besiegers at distance (approaching infantry or enemy artillery).

In the simplest trace italienne forts, this is all you will need: four or five thick-and-low curtain walls to make the shape, plus a bastion at each corner (also thick-and-low, sometimes hollow, sometimes all at the height of the wall-walk), with a dry moat (read: big ditch) running the perimeter to slow down attackers, increase the effective height of the wall and shield the base of the curtain wall from artillery fire.

But why stay simple, there’s so much more we can do! First of all, our enemy, we assume, have cannon. Probably lots of cannon. And while our walls are now cannon resistant, they’re not cannon immune; pound on them long enough and there will be a breach. Of course collapsing a bastion is both hard (because it is angled) and doesn’t produce a breach, but the curtain walls both have to run perpendicular to the enemy’s firing position (because they have to enclose something) and if breached will allow access to the fort. We have to protect them! Of course one option is to protect them with fire, which is why our bastions have faces; note above how while the flanks of the bastions are designed for small arms, the faces are built with cannon in mind: this is for counter-battery fire against a besieger, to silence his cannon and protect the curtain wall. But our besieger wouldn’t be here if they didn’t think they could decisively out shoot our defensive guns.

Via Wikipedia, Fort McHenry, in Baltimore, Maryland. This is the first trace italienne fort I ever visited (not that I knew that was what it was called at the time. The triangle bit blocking the entrance to the gate is a ravelin. By the by, for my American readers: there are a lot of good bastion forts in the States and Canada, but they’re generally much smaller (as you’ll see in a moment) than their counterparts in Europe.

But we can protect the curtain further, and further complicate the attack with outworks, effectively little mini-bastions projecting off of the main wall which both provide advanced firing positions (which do not provide access to the fort and so which can be safely abandoned if necessary) and physically obstruct the curtain wall itself from enemy fire. The most basic of these was a ravelin (also called a ‘demi-lune’), which was essentially a ‘flying’ bastion – a triangular earthwork set out from the walls. Ravelins are almost always hollow (that is, the walls only face away from the fort), so that if attackers were to seize a ravelin, they’d have no cover from fire coming from the main bastions and the curtain wall.

And now, unlike the Modern Major-General, you know what is meant by a ravelin…but are you still, in matters vegetable, animal and mineral, the very model of a modern Major-General?

Cinta muraria di Palmanova.jpg
Via Wikipedia, Palmanova, Italy, famous for being an example of a pre-planned, ‘ideal’ Renaissance city. Renaissance thinking about cities frequently fell on the idea of the ‘star shaped’ city – one easily circled by a bastion fortress – as the ideal shape of a city, with a large central plaza, as here.
Also note how the main curtain wall and its bastions are supported by a series of ravelins and even further off, several redans beyond the moat and glacis.

But we can take this even further (can you tell I just love these damn forts?). A big part of our defense is developing fire from our bastions with our own cannon to force back enemy artillery. But our bastions are potentially vulnerable themselves; our ravelins cover their flanks, but the bastion faces could be battered down. We need some way to prevent the enemy from aiming effective fire at the base of our bastion. The solution? A crownwork. Essentially a super-ravelin, the crownwork contains a full bastion at its center (but lower than our main bastion, so we can fire over it), along with two half-bastions (called, wait for it, ‘demi-bastions’) to provide a ton of enfilade fire along the curtain wall, physically shielding our bastion from fire and giving us a forward fighting position we can use to protect our big guns up in the bastion. A smaller version of the crownwork, called a hornwork can also be used: this is just the two half-bastions with the full bastion removed, often used to shield ravelins (so you have a hornwork shielding a ravelin shielding the curtain wall shielding the fort). For good measure, we can connect these outworks to the main fort with removable little wooden bridges so we can easily move from the main fort out to the outworks, but if the enemy takes an outwork, we can quickly cut it off and – because the outworks are all made hollow – shoot down the attackers who cannot take cover within the hollow shape.

Via Wikipedia, an ideal form of a bastion fortress to show each kind of common work and outwork.

We can also do some work with the moat. By adding an earthwork directly in front of it, which arcs slightly uphill, called a glacis, we can both put the enemy at an angle where shots from our wall will run parallel to the ground, thus exposing the attackers further as they advance, and create a position for our own troops to come out of the fort and fire from further forward, by having them crouch in the moat behind the glacis. Indeed, having prepared, covered forward positions (which are designed to be entirely open to the fort) for firing from at defenders is extremely handy, so we could even put such firing positions – set up in these same, carefully mathematically calculated angle shapes, but much lower to the ground – out in front of the glacis; these get all sorts of names: a counterguard or couvreface if they’re a simple triangle-shape, a redan if they have something closer to a shallow bastion shape, and a flèche if they have a sharper, more pronounced face. Thus as an enemy advances, defending skirmishers can first fire from the redans and flèches, before falling back to fire from the glacis while the main garrison fires over their heads into the enemy from the bastions and outworks themselves.

Via Wikipedia, a diagram showing a glacis supporting a pair of bastions, one hollow, one not.

At the same time, a bastion fortress complex might connect multiple complete circuits. In some cases, an entire bastion fort might be placed within the first, merely elevated above it (the term for this is a ‘cavalier’) so that both could fire, one over the other. Alternately, when entire cities were enclosed in these fortification systems (and that was common along the fracture zones between the emerging European great powers), something as large as a city might require an extensive fortress system, with bastions and outworks running the whole perimeter of the city, sometimes with nearly complete bastion fortresses placed within the network as citadels.

Via Wikipedia, Fort Saint-Nicolas, which dominates the Old Port of Marseille. The fort forms part of a system with the low outwork you see here and also an older refitted castle, Fort Saint-Jean, on the other side of the harbor. I was able to see this one in person (its even bigger up close), but alas, while there are vague plans to open Fort Saint-Nicolas to the public, they had not proceeded very far when I was there. Marseillais, if this changes, tell me!

All of this geometry needed to be carefully laid out to ensure that all lines of approach were covered with as much fire as possible and that there were no blindspots along the wall. That in turn meant that the designers of these fortresses needed to be careful with their layout: the spacing, angles and lines all needed to be right, which required quite a lot of math and geometry to manage. Combined with the increasing importance of ballistics for calculating artillery trajectories, this led to an increasing emphasis on mathematics in the ‘science of warfare,’ to the point that some military theorists began to argue (particularly as one pushes into the Enlightenment with its emphasis on the power of reason, logic and empirical investigation to answer all questions) that military affairs could be reduced to pure calculation, a ‘hard science’ as it were, a point which Clausewitz (drink!) goes out of his way to dismiss (as does Ardant du Picq in Battle Studies, but at substantially greater length). But it isn’t hard to see how, in the heady centuries between 1500 and 1800 how the rapid way that science had revolutionized war and reduced activities once governed by tradition and habit to exercises in geometry, one might look forward and assume that trend would continue until the whole affair of war could be reduced to a set of theorems and postulates. It cannot be, of course – the problem is the human element (though the military training of those centuries worked hard to try to turn men into ‘mechanical soldiers’ who could be expected to perform their role with the same neat mathmatical precision of a trace italienne ravelin). Nevertheless this tension – between the science of war and its art – was not new (it dates back at least as far as Hellenistic military manuals) nor is it yet settled.

Крепость Bourtange (Буртанж, она же Бауртанге, она же «Звездная крепость») — форт в Нидерландах на границе с Германией.jpg
Via Wikipedia, an aerial view of the Bourtange Fortress in Groningen, Netherlands. Built in 1593, the fort has currently been restored for its 1750s configuration, seen here.

But coming back to our fancy forts, of course such fortresses required larger and larger garrisons to fire all of the muskets and cannon that their firepower oriented defense plans required. Fortunately for the fortress designers, state capacity in Europe was rising rapidly and so larger and larger armies were ready to hand. That causes all sorts of other knock on effects we’re not directly concerned with here (but see the bibliography at the top). For us, the more immediate problem is, well, now we’ve built one of these things…how on earth does one besiege it?

Siege Math

Of course part of the answer to this question was ‘you don’t.’ Areas that became densely set with trace italienne fortresses – particularly the towns of the Low Countries – became almost impossible to conquer. The Army of Flanders, then arguably the finest in Europe, tried for eighty years to subdue the Dutch and largely failed: the cost of endless sieges of trace italienne fortified towns made the task effectively hopeless. Once again, I don’t want to imply that this is the only factor (it isn’t, by any means), but after the long series of remarkably decisive wars from 1450 to 1550, the trace italienne contributed to the frustratingly inconclusive (but expensive and bloody) wars of the following century.

At the same time, this shift back towards defensive stalemate didn’t lead towards more fragmentation – as the castle had – because trace italienne fortresses were too expensive for any individual aristocrat to build merely to protect his house. Not merely because of the massive fortifications themselves, but the large garrisons they required, either of full-time soldiers or town militia, which were simply beyond the resources of what was left of the old medieval aristocracy. Indeed, warfare in this period (both offensive and defensive) largely proved to be beyond the resources of Europe’s newly centralizing states; the Spanish crown, for instance, went bankrupt, primarily from military expenses, in 1557, 1560, 1575, 1596, 1607, 1627, 1647 and 1653.

It is of part and parcel of the era that as much as building and defending a trace italienne fortress was an exercise in mathematics, so was attacking one. Because the entire point of the fortress is to project firepower – often at great distances (with cannon) – the attacker cannot simply form up outside or just set up their artillery in an open field and begin firing; they’d be cut up by counter-battery fire before they had gotten very far. So the attacker had to set up their own earthworks, which naturally being based on the same principles and weapons as the defender’s, would resemble them.

First, the attacking army would generally set up its own fortified camp, outside of cannon-shot. Because that camp needed to be resistant to enemy attack either from the garrison of a relieving army, it was likely to be built in the same style as a trace italienne fortification, albeit with earthworks and gabions (wicker baskets filled with earth) in place of the heavier stonework of the fort. The attacker then has to isolate their target from help, preventing the defenders from leaving, or supplies or reinforcements from arriving. The act of enclosing a besieged settlement in a wall is called circumvallation (recall our word vallum there; this is ‘walling around’). The act of constructing a line of outward facing defenses to defend that line from attack by a relieving army from behind is called contravallation. Armies in this period would do both.

Diagram of the Siege of Breisach, 1638, showing both circumvallation and contravallation (note how many of the defender’s bastions point outward.

The first such line of defenses was often started from the fortified camps and was built effectively out of range of the fort; this was the ‘first parallel.’ Now, by the time this project was well along, both the defenders and the attackers could do some basic calculations. They both might have a sense of how quickly reinforcements could arrive and if they were likely to be large enough to give battle or lift the siege. Both sides also know how long their supplies will last and can probably have a decent guess of how long their opponent’s supplies will last. And at this point, they can both calculate fairly well how many meters of earthwork and trench the attackers can dig per day and how many they need to dig to complete their siege operations.

But – and this is important – no one wants this siege to come down to its conclusive, final assault. The attackers don’t want this: every day their siege army sits out here, it is eating money such that each day wasted besieging this town limits what this army can accomplish overall before supplies and money run out. Moreover, the actual assault is likely to incur very high losses on the attackers, because even with a breach, they have to cross all of that open, fire-swept ground and then force the breach in close combat – and the defenders will know exactly where they are going days in advance. On the other hand, if the defenders make the attackers go through all of that effort, danger and death and lose – and they must assume the attackers wouldn’t have laid siege if they weren’t confident they had enough men to take the breach when it comes to it – then the city would be looted, its populace raped or massacred as the attackers vent their rage on the city. This was, at the time, considered the normal result of holding out, to the point that it seems to have been general practice that it was appropriate to wait something like three days before beginning the process of getting control of an army that had breached a city in this fashion.2

So once the attacker has completed that first parallel, he is going to send a message to the garrison, announcing that he has done so and offering them the chance to surrender. The standard terms for such surrender was called the ‘honors of war‘ – normally the defenders would be permitted to march out, with its flags flying, bayonets fixed, matches (for their matchlock muskets) lot on both ends and ‘ball in mouth’ (that is, a musketball held in their mouth ready to be swiftly loaded as protection against treachery). The defeated army was generally required to turn over its arms, but generally allowed to march back to their own territory. And finally, a town that surrenders like this might have to pay a ransom, but ought to be immune from pillage. To modern readers, these sorts of rituals seem quaint, like having a battle break for tea in the midafternoon (a thing that, to be clear, did not happen), but in fact these were fairly hard-nosed considerations: generous surrender terms aimed to induce a garrison or town to surrender and so spare the attacker both the time but also the blood of storming the place, because after all the goal here isn’t to destroy the enemy garrison but to get control of the town.

One that first parallel is completed, assuming the defender, upon doing the math, doesn’t decide the matter is hopeless and just give up, the attacker now proceeds to begin digging his works forward to set up advanced firing positions (most of the digging was done at night when enemy artillery couldn’t accurately fire at the work parties); there were typically three parallels, the first two providing protection to the digging works and the third parallel, dug into the glacis, providing the firing position directly into the structure of the fort.3 Once the cannon were emplaced, the attacker might again report that he was prepared to begin firing but if the defenders would just surrender, we could all skip that nasty business. If not, the attacker’s cannon – now secured in their own trace italienne-style firing positions – would start working on the enemy fortifications in a gunnery duel (since the defender’s guns are firing back). Progress here would mean both demolishing ravelins and other outworks which shielded the main curtain wall, as well as storming assaults on various outworks to take them and deny them to the enemy (Americans may note effectively all of these steps in the Siege of Yorktown (1781), albeit on fast-forward since this was a siege of a fairly small town defended merely by field fortifications rather than a large trace italienne fortress complex). The final option to surrender came once the curtain wall had been breached (there was little use in trying to ‘rush’ the breach since it would take days to produce so everyone knew where the final fight would be). The defender then had the terrible choice of either surrendering or risking the terrible slaughter that would follow if the breach was forced (as it was very likely to be).

This whole process could take a really long time and it involved a lot of digging, but it was almost mechanistic in its push towards success. In a sense, those demands forced European states to develop the sort of state capacity that had been the norm under Rome or in China in order to run this new version of the ‘big army’ siege playbook which demanded such tremendous amounts of work. As I’ve noted elsewhere, sieges of these sorts against large trace italienne complexes could last a long time; Parker (Military Revolution, 13) notes the siege of Breda in 1624 lasted nine months and was fairly short while the siege at Ostend in Flanders in 1601 lasted three years and was fairly long, to give a sense of the range.

British Shells and French Polygons

Naturally while these siege methods worked, they took a long time, cost a lot of money and thus limited the potential scope of military operations, so as you might imagine there were also efforts technologically to try to develop weapons that would be more effective against trace italienne style forts. While artillery usage improved tremendously from 1500 to 1700, it took a surprisingly long amount of time for those weapons to appear, but they did eventually appear, in the form of effective explosive shells.

Of course the basic idea, taking an iron shell, filling it with something that explodes and flinging it at the enemy, wasn’t new. But making exploding shells actually work demanded a lot of math. The physical technology was shrapnel shell: a shell designed to explode into small, lethal high speed fragments (often including not merely the metal shell the explosive charge was in, but small metal balls placed within it); the first of these was developed in 1784 by Henry Shrapnel (1761-1842), whose name eventually gave us the word shrapnel with its meaning. A shrapnel shell that burst directly over a bastion could easily kill most or all of the soldiers manning the cannon there, allowing an attacker to ‘clear’ the fortifications from long range. The potential of this kind of attack was recognized fairly quickly, but making it work took some doing. These exploding shells, after all, are the ‘bombs bursting in mid-air’ which nevertheless failed to take Fort McHenry out of commission (though at the same time, imagine what it means that the British fleet – and the American defenders! – considered it plausible that a single nights bombardment might knock out the small, trace italienne-style fort).

Via Wikipedia, the inside of a casemate, in this case a mid-19th century casemate at Fort Knox (not the one you are thinking of), Maine.

The problem is that the shell needs to explode at just the right moment in its arc to send its shrapnel raining down at the defenders. That means both that the shot needs to be accurate – the defenders need to be in its path! – but also that the fuse needs to be precisely timed to that very moment. Achieving that required both much better cannon and far more precise ballistics. Luckily for European gunners (and unluckily for their targets), the scientific and industrial revolutions in Europe were in the process of furnishing both and by the second quarter of the 1800s, European gunners had gotten very good at this trick. One may, for instance, consider Tonio Andrade (op. cit.)’s description of British gunners tearing apart Qing-dynasty Chinese forts in the First Opium War (1839-42), forts that were designed to resist cannon to see the effectiveness of European gunners against open-topped forts using shrapnel shells by the 1840s.

Via Wikipedia, three tiers of artillery casemates from a mid-19th century fort, Fort Point, in San Francisco.

The response to these shells was what is sometimes called the ‘polygonal fort.’ These forts come in substantially simpler shapes than the almost baroque designs of the trace italienne, but their major innovation was in placing the defensive guns in multi-story stone or brick casemates, big vaulted chambers built into the walls of the fort. The basic principles of these new kinds of forts were proposed by Marc René and Lazare Carnot in France, with the first fully developed examples of the type emerging in the first decades of the 1800s. The industrial revolution had made cannon cheaper, so the possibility of mounting multiple stories of cannon, one atop the other, to generate crushing firepower was possible (and of course shrapnel and canister shot meant that such forts could develop enough firepower that they couldn’t be approached). For Americans, the most famous example of such a fort is Fort Sumter, but many civil war era permanent forts were of this style. To control the approach, the ditch – which was preserved – was defended by caponiers, covered shooting positions that projected into the moat with firing positions to enable the defenders to fire down the base of the walls. By being covered, the caponiers were shielded from shrapnel shell and by virtue of being entirely submerged down into the ditch, they avoided simply being battered apart by enemy direct-fire artillery.

Via WIkipedia, a diagram of a caponier, projecting out into the ditch in order to provide that enfilade fire.

That said, the polygonal style of fort itself wouldn’t last very long. The improved machining of the industrial revolution had made it possible to rifle cannon the same way that muskets could be rifled; as with muskets, such rifling would allow for much greater accuracy and power. During the American Civil War (1861-1865), gunners – particularly United States gunners, since the US Army, being generally on the offensive, tended to do most of the attacking forts apart from that first one and also had far better access to modern rifled cannon – demonstrated that these newer, larger and more powerful rifled siege guns could reduce brick and stone polygonal forts to rubble with startling speed. Fort Pulaski, in Georgia, a single-story (plus the rampart) polygonal fort, was breached in just 30 hours by US rifled cannon (James and Parrott rifles, in the event) under the command of Quincy A. Gilmore.

By contrast, earthworks – that is, field fortifications like trenches – held up much better under bombardment. Indeed, in the case of the famous Fort Sumter, after the US Navy blockade essentially reduced the by-then-Confederate held fort to rubble, Confederate gunners mounted their cannon in the ruins, essentially turning the shattered brick into earthworks which couldn’t also be flattened (though of course had this fort not been on an island, the attacker could have simply stormed it at this point). That said, it is important not to overstate this; field works in the civil war mostly remained breastworks (that is, built above ground) rather than trenches (though these were still used in sieges) and the emergence of a sort of proto-trench warfare had as much if not more to do with the decision by US commanders (particularly Grant) to remain in contact with Confederate armies in order to pressure them as it had to do with firepower.

Via Wikipedia, the shattered remains of Fort Sumter.

The other development in the offing which would be even more potentially fatal to large, obvious fortresses was the emergence of other explosives than gunpowder. While dynamite, patented in 1867, was generally too unstable to be used in exploding shells (it tended to explode in the barrel), but effective high explosive shells which could blast apart walls and earthworks (penetrating and then exploding) began to emerge in the 1880s, forcing new fortification designs, which we’ll discuss as the last part of this series next time. But not next week. Next week is Christmas Eve and I’m taking it off. So I’ll see y’all on the 31st.

  1. A non-exhaustive list (some dates approximate): the Ottomans absorb Byzantium (1453), Serbia (1459), Morea (1460), Trebizond (1461), Bosnia (1463), Albania (1468) and Theodoro (1475). Muscovy absorbs Novgorod (1478), Tver (1485), and Pskov (1510). Spain absorbs Aragon (1479), Granada (1492), Navarre (1513) and parts of Burgundy (1482). France absorbs Burgundy (1482), Provence (1486), Auvergne (1527), and Brittany (1547). Austria absorbs Bohemia (1526) and splits Hungary with the Ottomans (1526). And Poland destroys the Teutonic Order (1521) before Poland and Lithuania absorb each other into the Polish-Lithuanian Commonwealth (1569). There’s also a lot of smaller-scale consolidation within the Holy Roman Empire, but untangling all of the lands and titles there is beyond my ken.
  2. Needless to say this description of the realities of early modern European warfare should not be taken as in any way approving of it. As I’ve noted elsewhere, the warfare of this period was remarkable in its destructiveness.
  3. The full three-parallel method comes relatively late and is codified by Sébastien le Marquis de Vauban (1633-1707), though some form of ‘dig forward until you get to the glacis, then blast them’ had been in use much longer

190 thoughts on “Collections: Fortification, Part IV: French Guns and Italian Lines

  1. As an alt-history/time travel scenario, would the introduction of something like Roman concrete (or whatever would have been produceable at the time – assume unreinforced due to unavailability of steel) have made much of a difference to the construction of star forts?

    1. The question you’d want to ask is, what would you do with the concrete that you can’t do with huge piled-up and tamped down earthworks, optionally faced with cut stone? I’m not seeing a lot of applications that are relevant, but I may be missing something.

  2. A quick question.

    Do anybody know how all these very technical kind of fortification interacted with local geography ?

    In mountains where space would be limited for a full star fort ?
    Along cost or rivers ?
    Around cities too big to be fully encased in fortifications ?

    Was the playbook adapted ? or could one with enough work just wave off geographical constraints ?

    1. I understand that Vauban tried to pop his forts in the Pyrenees in the valleys where the population was healthiest where possible so that the garrisons would be less troubled by sickness.

    2. I did some googling and I can’t really find anything, but perhaps the fortresses in mountainous areas would be built in the less sloped parts of a valley (which probably had most of the farms anyways)? At the coast or a river, you could have a semi-circular star fortress and then simpler fortifications to the river (since ships are much easier to sink than it is to fire at enemy batteries built into star fortification type fortifications, if the enemy tries to breach them you will likely be able to sink a lot of his ships and that sucks for him), or in case of a river you might have a seperate smaller fort on the other side of the river blocking the enemy from building batteries on the other side of the river. An example of this is Antwerp.

    3. Coastal forts defended pretty much every important coastal city and harbor of size, because ships had cannon could easily drop off a shore party for a surprise assault, and generally needed to be defended against.

      I happen to live in a small coastal former garrison town where the 17th century fort is facing the sea and was originally connected to wall encompassing most of the town itself. The fort itself is placed to be able to fire on enemy ships as well as serve as the lynchpin of the defenses in case a wandering army came along to siege the town. The sea-facing side was clearly the one that most concerned the designers as significant outworks were built on an artificial island to cover entrance to the harbor. Coastal forts have the advantage that, being on the coast, you could easily get a wet moat instead of just a dry moat, though I’m sure that came at the cost of being harder to dig out in the first place.

      1. I’m wondering where Henry VIII’s artillery castles, Deal, Sandwich and Walmer fit in with their curved rather than pointed bastions.

        1. As I recall, they represent a transitional form between the round-turreted medieval styles and the full-on trace itallienne. There might also have been a regional aspect involved.

          1. Interesting that everybody whent for sharp angles. I can only presume that they provided better firing fields or something over curved bastions.
            It can’t have just been an aesthetic preference for stars over cloverleafs!

          2. Sharp angles provide firing lines with no deadzones (areas where lines of fire would be blocked by the tower itself). Curved towers create deadzones around the base.

      2. Coastal forts had one other advantage – the town or installation they defended was not likely to expand in that direction, and transportation links were limited to a small known set of anchorages. Land-facing fortification constantly had to deal with cities outgrowing them, or civilian authorities objecting to this massive obstruction of peacetime transportation.

    4. Every such fortification took account of local geography, which also happened with castle building (for example, Chateau Guillard). A good example of a trace italienne one in relation to local conditions is Besancon: Note the quote in this wiki article: “The buildings that Vauban undertook [were] not randomly constructed and responded to specific needs.”

      The Belgian and Netherlands ones were probably the most geometrically regular, because they were often built on very flat locations.

    5. They tried to take advantage of local geography as much as they could (rivers, slopes, etc.) but there is also a remarkable degree of remouldering the terrain itself going on.

    6. There are quite a few of them straddling what used to be the border between the Ottoman Empire and the Habsburg Empire, on the Sava and Danube rivers, like the Brod fortress or Petrovaradin. The latter in particular uses the river quite extensively to protect its back (although there are some bastions on that side as well, but less and I think also smaller ones).

    7. If you want to see how these principles interact with mountains, you can look at the Bastille of Grenoble, which was an active fort from 1590-1860. There are multiple lines of bastions going up the mountainside, although they aren’t nearly as pointed as the ones shown here. Since the mountain continues above the Bastille, there is also a backwards facing moat and bastions to defend against attacks from the mountain.

      Along the coast or rivers, the moats were often filled with water. On the east side of Copenhagen, star shaped ramparts and moats still exist. It is now an anarchist community (Freetown Christiania) instead of a military establishment.

    8. Mountain fortresses were affected by geography. The area will be covered in snow 4-7 month every year and there will be rains in spring and autumn for 2-4 months. A besieging army will have about 3-5 months to move in, conduct the siege and move out. The area would have limited agricultural productivity and the communication lines will be impassible for heavy transport during mud or snow season.
      Castels and forts were also built sideways from the lines of communications. The local forces will fight usualy in some mountain pass to block an invader. If they failed they will basically allow free passage and avoid a siege. A siege will devastate the local farms and destroy the fort just before winter sets in.
      The usual method for moving an army through mountain passes was to buy the access rights and not to fight for them. Hannibal fought outside the Alps, The Moguls paid for moving their army from India to Afganistan. It was cheaper, faster and more profitable for both parties. So there was no pressure to build star forts, only fortresses with walls strong enough to absorb a few days of bombardment.
      Mountain passes were usually secured at entry and exit points, in hill or plain country. There will be star forts and heavy defences.

  3. Typos:
    “the concern that artillery much produce a breach in the wall”
    much or might?

    “(whicker baskets filled with earth)”
    whicker or wicker?

    “Progress here would mean both dembolishing ravelins and other outworks”
    dembolishing or demolishing?

  4. Thanks for these, Brett – I’m really enjoying the series.

    Question, though: what about mining in this period? My understanding was that it was quite common (especially as gunpowder made it potentially a very spectacular way of breaching a curtain wall) and was carried out with the same scientific rigour as the siting of batteries. And so it was a key piece of the negotiations you mention. I know you were focusing on ‘the guns’ this episode, but are you going to cover it separately?

    Anyway – cheers for this series, and have a very Happy Christmas!

    1. I gather mining (and counter-mining! The defenders could get in on the action too!) were somewhat dependent on the local soil conditions – more difficult if the soil is rocky or the water table is high.

      1. Though in some circumstances (surely exceptional) you could get mining and counter-mining running even through granite– the examples at St Andrews (1546) are still passable, being through the solid rock

  5. In Note 1, please change “Aragorn” to “Aragon”!!

    I’m currently playtesting a game on the War of the 3 Sanchos (1065-67) that includes constant references to the Kingdom of Aragon. I’m trying to remain patient when reminding my playtesters of both the correct pronunciation and spelling!

    1. If playing EU IV as Aragon, you have missions like defeating Saruhan (in Anatolia) or becoming king of Gondar (in Ethiopia).

    2. As an aragonese I was going comment the same. You also got my interest about your game, it is not the most popular time and location. It is nice to see this kind of attention to that era.

  6. One thing to note about the preference for surrender: In addition to the issue of casualties there tended to be a concern about wanting to take a city intact. By tradition a city taken by storm was given over to sack by the soldiers (who, in the timeframe were often mercenaries) and so it was in the interest of both the attacker and defender to prevent this (because a sack could destroy a town you sought to take intact, and even if it didnt, it might delay furhter operations for days as soldiers ran around stealing stuff, or setting fire to things) the 30-years War sees a few examples of cities being taken by storm and the commanders basically having to wait a few days to get their armies in order so they can continue with whatever they are doing.

    Mining was also an important aspect, though one disadvantage is that it consumed huge amounts of gunpowder.

    Another thing is that siege artillery (at least in the 1600s) was often different from field guns: Much larger and heavier, and so more difficult to carry around, there were several times during the 30-years war were swedish armies (constructed in northern and eastern europe were italian-style fortresses were more rare) had trouble besieging fortresses because while they carried plenty of artillery it was of the lighter field-gun types. 3- and 6- pounders.

  7. Hey Bret I see the earlier posts referenced roman forts, but don’t you know the Romans were the invention of the inquisition?

    It’s all just greece man.

  8. “[…]no one wants this siege to come down to its conclusive, final assault. The attackers don’t want this: every day their siege army sits out here, it is eating money such that each day wasted besieging this town limits what this army can accomplish overall before supplies and money run out.”

    Maybe I’m missing something here, but wouldn’t this be exactly the other way around, ie the attackers would actually WANT the conclusive swift assault to avoid their siege army sitting around eating money? Surely the actual reason for not assaulting was in fact the one mentioned immediately after this quite, ie the prohibitive losses that they would suffer in case of an assault, to the point that the “sitting around eating money” is outweighed by the potential risk to lose a boatload of troops (and also, potentially, the siege)? Just a minor detail, but since we ARE on a blog dedicated to pedantry… 😛

    And, anyway, merry Christmas to you!

    1. I think the point is that there is no such thing as a (successful) swift assault against a properly defended star fort, so it’s either a negotiated surrender or a *very* time-consuming siege in preparation for the conclusive assault.

      1. Thanks, and yes, that’s definitely my take away too. It just the somewhat weird wording that struck me as odd.

        1. Nobody wants the final assault, because if the final assault is done after a long siege, you’ve wasted a lot of time and money and then many soldiers on top of it all. And if the final assault is done before carrying out a protracted siege, you’ve done even worse- your army’s too dead to be of much use, and if you wanted that you wouldn’t have brought them along in the first place.

    2. If the attackers could magically skip ahead to the conclusive final assault, they’d be happy with that, but the defenders won’t let them. The only way they get there is by digging a lot of trenches, which means a lot of time and money spent on the siege.

    3. Perhaps you are thinking of a “hasty assault”? That was a thing against medieval forts (described in, since a failure to keep adequate watch was plausible when the fort was designed to be crewed by, sometimes, just a few dozen soldiers. For a trace italienne fort, crewed by several thousand soldiers (to develop all that firepower), watch-keeping was basically a solved problem.

      Yes, I’m treating fortifications as a type of crew-served weapon.

      1. Fortifications are just landed warships, after all, right? Or is it the other way around, and warships are fortifications with propulsion systems?

        1. No, warships are MUCH more vulnerable to damage than fortresses are. Warships are almost more the equivalent of sea-going horse archers.

        2. I believe the British navy still has rules on the books for commissioning islands as ‘ships’.

          1. I’ve read analysis of the Battle of Midway that described the island as an aircraft carrier that couldn’t be sunk.

          2. ‘Stone Frigates’ are still a thing – the RN classifies shore bases as ships so that the people posted there can be entered into the rolls of a ship and thus placed under naval discipline.

            The law establishing the navy’s authority over it’s personnel dated from a time when the RN ran all of its depots and training centers from hulks rather than onshore facilities and so was framed around navy crews being on ships. As the RN moved from hulks to permanent bases onshore, they came up with this legal hack to avoid the hassle of getting a new law passed through parliament.

          3. The RN’s shore establishments are still (often) named HMS WhatBaseIsThis – though this has not always been observed. (As far as I can tell, for example, this naming convention was not used for Scapa Flow.

    4. The context is that they’d rather have the garrison surrender. It takes a good amount of time to get to the point where a conclusive assault is feasible.

    5. One should bear in mind that breaches tend to be fairly narrow, prior to explosive shells. So even if you can make a breach, you are now proposing to assault a defended position that is maybe four to ten metres wide, while exposed to fire on the approach. The survivours of this little exercise are then to fight, generally hand-to-hand, to break through whatever force the defender has mustered at the breach, which you cannot suppress, or even meaningfully inconvenience until you get to the breach itself.
      Mind, it can be done, and it was done a number of times. However, it also invariably led to complete loss of control over the troops; commanders could not prevent sacks, even if they wanted to, as happened to Wellington at Badajoz.
      NB also that Wellington lost almost 5,000 of his 27,000 soldiers in the affair, then had to spend three days getting his army back under control. This despite three separate breaches, and a night attack, to reduce the effectiveness of French fire.

      You can do that sort of thing only so many times before you run out of soldiers.

      1. A storm is clearly not an optimum strategy even for the attacker. And of course it’s a nightmare for the civilian population.

  9. Honorable mention: Hussite Wagon Forts (1419–1436, Czechia). Hussites themselves were proto-protestants, named after Jan Hus, burned on a stake. Under the leadership of Jan Žižka, they figured out how to build forts on the spot and reap the benefits of defensive warfare on the battlefield. They were successful at beating traditional medieval heavy cavalry using early firearms and cannons, until cannon development made their tactics obsolete. Still, they had an impact: pioneer tactics in Wild West were basically the same, and they prompted the reforms of Polish-Lithuanian cavalry which resulted in winged hussars.

    Monty Python style animations and a charming (Swiss??) accent

    1. Indeed…the Hussite Wars are supposedly the first time firearms were successfully used on large scale in European warfare, and also supposedly the reason that some of the terms for objects such as pistol or howitzer entered the military parlance through Czech language.

      Or at least I read that on few occasions. I wonder whether someone with more experience with this period can confirm? Or is that just an urban legend and folk etymology? At the very least, the Hussite wars DO predate the blasting of Theodosian walls by a few decades (albeit Hussite wars are mostly known for the usage of smaller arms rather than big siege cannons, AFAIK).

      1. I always understood the term pistol to come from the french, via a word originally used for a type of sword grip, and deriving from the word for part of a plant.

      2. For what it’s worth, Wiktionary says that pistol and howitzer come from Czech (through other languages).

        Pistol from píšťala meaning whistle or tube, and howitzer from houf meaning crowd or flock.

      3. According to one of the youtube comments, “Crowds are houfy in Czech”. In the video you see a cannon labeled as “houfnice”. I speak a related language so I’m sure it’s actually plural (ends with “e”). In Polish, “hufiec” is a word for a retinue. As you see the word changed meaning a bit because howitzers are not some kind of grapeshot. Both “Hufnica” and “haubica” (singular, feminine) are words in modern Polish although hufnica is just for the historical type of short barreled crowd cannon.

        Pro tip: Wikipedia has a very fun feature on the left where you can switch language. Sometimes it’s more precise than a dictionary.

        The most popular word that we owe to Czech language is definitely “robot”. One article says it comes from the Karel Čapek’s play “R.U.R.” and says “robota” means forced (serf) labor. Couldn’t confirm that with Google Translate, but in Polish “robota” means drudgery.

        1. houfnice is both singular and plural (in nominative). Czech often changes an original -a to -e (and -u to -i etc) in originally palatalized contexts, leading to forms which look strange to speakers of related languages.

        2. Čapek’s “Rossum’s Universal Robots” is the source of the English word ‘robot’, my understanding is that the specific noun form of the verb was a new coinage for Czech, and so none of the many existing English words for low-prestige unfree laborers would have served to translate that sense of coining a new word.
          It’s been twenty years since I read it (in English), but the choice to use ‘robot’ really did make the play strike the mind much more effectively, IMO.
          It’s also astonishing how influential the play is outside of the loan word; a huge portion of works featuring artificial humans are more interested in the questions raised in RUR than in those raised in Frankenstein, and {(SPOILER)} the play’s positioning of a humanity-ends-humanity event as a thing that can leave hope in its wake is an increasingly-popular theme in fiction and non-fiction today.

        3. In Croatian, “rabota” (nowadays a rarely used word) means work that is heavy, exhausting. Originally, word was used in the meaning of the work that a serf owned to the feudal overlord; another term for this – and one that dominates modern historiography – is “tlaka” (which in today’s parlance means “oppression”).

      1. The channel is run by Roman Schönenberger and Sandro Andreatta (hence the name) history students from Bern, Switzerland.

        1. Ah, okay. I wonder how I got the impression that the narrator is Dutch, since Dutch and Swiss German are, uh, pretty different.

  10. Fun fact: all this work on cannon enabled the piston to be precise enough, leading to the evolution of the steam engine.

    1. And then the machining and metallurgical techniques that were used to make steam engines better were also used to improve guns. A “virtuous” cycle

      1. Similarly, the mid-19th-century demand for steel for artillery had Napoleon III telling Henry Bessemer that it would be valuable if someone could figure out how to mass-produce it, which facilitated our modern build-everything-out-of-steel world.

        1. Related fantasy worldbuilding question which that reminds me of: some wizard enchants a hat, essentially as a prank, which accelerates hair growth by several orders of magnitude without taxing the wearer’s metabolism. Somebody puts the hat on a sheep, suddenly you’ve got an extra million sheep worth of wool production supported by the same amount of pasture – and it’s not particularly difficult to duplicate the enchantment. What sort of effects would that have on a premodern economy?

          My first thoughts were that thread and cloth would still cost about the same, at least in the short term, since surplus material isn’t reducing the amount of work involved in spinning. Instead, excess raw fiber would be overflowing into serving as a substitute for thatch roofs, binding material in clay bricks, and burnable garbage as a heat source. There’d also be some trade disruption as whoever lacks access to the magical boost sees their wool exports devalued.

          1. Magic systems in fantasy literature / TV often break one or more fundamental laws of physics that exist in our universe. If applied at scale, the result would be some kind of post-scarcity / singularity world and economy that looked more like Star Trek or the Culture.

            As a commentator observed in a previous discussion most authors, and their audience, want a medieval world plus a bit of magic. The better world builders therefore make magic some combination of being too expensive / hazardous / corrosive to be widely used.

          2. Like fortifications, you have to see the system as a whole, and there are endless possibilities in having magic as a commonplace resource, although I can only think of a few authors who use it that way. Lawrence Watt-Evans does a reasonable job in his Ethshar series and I take a stab at it in my Tales of the Wild. Sprague de Camp’s Unbeheaded King is another.

          3. More use of quilted armor? Outer container just stuffed tight with wool.

            I think burning hair is supposed to smell bad but still, you’ve now got a large supply of a kind of fuel.

          4. Wool can be turned into felt without spinning, and IRL the Asian nomads used a lot of the material for clothing and for covering yurts. Incidentally, if you find yourself with an excess of fibre crops (e.g. hemp), you can equally choose between spinning it (to get canvas) and making paper from it.

            As mindstalko points out, burning wool smells terrible (next time you or a member of your household cuts their hair, try it). However, I think that cheap (zero-metal) medieval armor IRL *was* commonly felt (possibly strengthened with glue, analogously to cuir bouilli, or perhaps a different material), when not a buff coat (see or cuir bouilli (I find this believable: For peasants, the quantity of spun fabric necessary to make a 20+ layer gambeson would have been their single most valuable possession, they wouldn’t have turned it into armor.

          5. Counterpoint to above: Same amount of wool in the system, but spending resources on fewer sheep means more diversified flocks.

      2. Much more direct than that. The cannon maker who made the first pistons was the first non-mining industrial user of a steam engine.

  11. What effect did these sieges have on the less local countryside? The city or immediate environs was obviously likely to get wrecked but what about the areas not directly implicated in the siege? Did armies still scour the countryside with foragers looking for supplies? Or was there an attempt to leave farms and their villages intact so long as they were denied to the enemy?

    1. There was quite often a lot of foraging, as I understand it.

      However, in areas where this kind of fortification was thick on the ground, the two sides of a war often had very extensive networks of fortresses. And they were fighting over relatively small areas because an army couldn’t march for more than a few days without smacking into a fort anyway. So, if I recall correctly…

      It was at this time that you started to see the post-medieval European armies actually trying to fight with a supply line to friendly military bases (star forts back in friendly territory). Indeed, because of how generally slow and positional this kind of warfare was (since the ultimate objective of most military operations was to deliver a siege to an enemy star fort no more than a few days’ march away)… The paradigm became more common, although armies still foraged when and as opportunity arose.

      Again, this may be me being off base, but I seem to recall that one of the things that made Napoleon unusual and borderline revolutionary is that he actually reversed this trend somewhat, subdividing his army into columns that could plausibly subsist off forage, and cutting loose from his slow-moving supply lines when he saw an opportunity to accomplish something.

      Please take this with a grain of salt. Would appreciate commentary from those more qualified.

  12. How many of the polygonal forts were actually built primarily for use against attacking armies? As I understand it, the main reason for the survival of stone/brick fortification was that ships couldn’t batter precisely in the way that land-based cannon could, and it was rifling that really undermined them by allowing single hits to do serious damage. Because a lot of these were built to fight ships. (All of the ones in the US, for a start.)

    More broadly, I find this era interesting because this was when serious coastal defenses started to be a thing, unless I’m missing something about Roman fortifications on the coast.

      1. To expand on Ian’s reply, Bret may have recommended it to you, but I’m the one who wrote it. That’s why I was asking. The link was supposed to be to part 3, but I must have screwed up the html.

        1. Haha I apologize Bean, I should have put 2 and 2 together. I just saw “Bean” and assumed you had really enjoyed Ender’s Game. Big fan of your blog.

        2. Haha I apologize Bean. I should have put 2 and 2 together. I must not find “bean” to be that distinctive of a name just because I assume everyone on these blogs loved Ender’s Game. Really enjoy your blog–it’s always my first recommendation whenever anyone asks me anything naval related.

          1. oh and now I accidentally double posted–the first one did not show up! not my day for interneting

          2. Not a problem. I just found it amusing. As for Ender’s Game, yes, I did, although there’s a second joke involved. And thank you.

    1. Me too. The stars within stars is very attractive.
      The designers of Game of Thrones series gave Dragonstone a very angular design with extremely pointy bastions, apparently for purely aesthetic reasons.

  13. As you write, some ancient thinkers also saw fortification as more if a science than an art. The defense of Syracuse was definitely described as an “exercise in geometry” by Roman sources

  14. So a couple years ago I read the Silk Road and one of the off-hand claims made in it was that the reason the European Conquest/Colonialization of the Americans succeeded so well, was the Europeans excellence at building and scaling fortresses. After reading, I found the author on twitter (when he was open to questions) to ask why they were so good at it, and got the unsatisfactory reply (more or less, I’m quoting from memory here) that who knows why some societies evolve one way and not another. It thought that was an odd response from an historian, because we so often do know or at least get an inkling. But in any event, it strikes me reading this that maybe the Europeans did not distinguish themselves in this manner. I don’t mean they were bad at it but that lots of societies had this skill, so this line doesn’t cut it as a reason

    1. The Portuguese used their combination of naval power and fortbuilding extremely effectively in India. They would seize control of defensible land, build a fort, and then the Indian kingdoms were incapable of driving them out. By the time Cortez conquered Mexico, the Portuguese had 8 such strongholds scattered along both the west and east coasts of India. In 1570, all the kingdoms of southern India allied with each other and various Indonesian states, mobilizing over 200,000 men. They only won one siege in the entire war and Portugal emerged triumphant after 5 years. At the Siege of Malacca, 300 Portuguese resisted a 3 month siege and killed half the 15,000 attackers.

      I think it is overestimated how long it took for Europe to achieve military superiority, not just in the Americas, but also Asia. By the early 1500s, it was already a competition in India between the Portuguese on one side and an alliance of the Ottomans, Mamluks, and Venetians on the other. The powers would change over time, the Dutch, English, Danes, French would come latter, but the general pattern of naval-focused trade wars between western powers and periodically seizing port cities would continue for the next 250 years, with the Western powers forcing concessions or picking winners in internal political struggles. This would last until the Seven Years War, when the British East India Company gained a dominate position and started conquering and directly ruling large parts of India.

    2. European conquerors were very much an Outside Context Problem for the original inhabitants in the Americas. Some of them, for instance the tribes in the North West (or the Maori in New Zealand), were already using fortifications, but naturally these were designed / evolved against attacks by the neighbours, not against threats from another continent.

      The main article mentions the 1494 siege of Mordono, which showed that just one generation of improvement in artillery was enough to make existing styles of European fortification obsolete and ineffective. And this was against people who’d already been using gunpowder weapons for a century. When the Europeans showed up in America with the same cannon and muskets, they could blast any native fortification into splinters, and had so much firepower that even a simple wooden stockade could be held against large numbers of native attackers.

      So yes natives could be good at fortifications (but not all were, just as in Eurasia), but the European conquerors had too much of a head start.

      As for the more general problem of why Europeans conquered the Americas and not the other way around, that’s a whole other complicated topic itself. I quite like “Guns Germs and Steel” by Jared Diamond.

  15. I’d be curious as to what effect, if any, naval cannon had on sieges of island or coastal forts/cities. I never quite understood why ships in the age of sail tended to have huge numbers of cannon compared to contemporary armies and siege trains, but they always seemed to avoid contact with their landbound peers that on paper they massively outgunned.

    1. The forts:
      * had guns in “higher” mounts, meaning they could fire farther more effectively.
      * could use heated shot, which ships couldn’t (safely) and against which ships were WAY more vulnerable to than forts
      * forts have deeper magazines, meaning they can engage earlier (force-multiplying their range advantage)
      * forts can mount heavier weapons than ships, meaning (again) more range, and more impact on the target
      * finally and most importantly, ships are way more fragile than forts.

      Forts can sink ships at a range that the ships can’t even deliver effective fire against the forts at

        1. It’s approximately what it sounds like: you put your solid shot in an oven before loading it into the gun. Especially against a wood construction like ships of the era, this makes it into both a kinetic and incendiary weapon instead of being only a kinetic weapon.

          Running such a furnace on a ship not only would consume fuel they probably couldn’t afford to carry, but also it is an enormous fire hazard itself, as well as if anyone accidentally dropped one of the heated projectiles.

          1. Wikipedia claims warships did (rarely) use heated shot, and that the USS Constitution was fitted with a shot oven for use with her carronades (short-ranged low velocity cannon), but I don’t think it was ever used in combat

          2. @ianargent- I thought the shot furnace on the Constitution was for the main battery, not the carronades. Specifically, it was supposed to be used to heat shot for the stern chase guns in the event of pursuit by a more powerful ship, in the hope of forcing the other ship to break off the chase to put out the resulting fire.

            The page on the Constitution museum’s website seems to bear this out:

            With only one relatively small furnace, one ladle and set of tongs for moving the hot shot from the furnace to the gun, and an extended loading procedure to reduce the risk that the hot shot would ignite the powder charge on the way in, there was no question of firing a heated broadside- by the time the last gun was loaded, the shot in the first one would have cooled!

            On the other hand, I imagine fuel wasn’t an issue- the furnace was rarely in use, and seems to have used the same fuel (which was apparently wood) as the ship’s galley.

          3. There’s a reason I prefixed with “wikipedia claims” – I did not look at the sources

      1. Also the limits to their mobility.

        New Orleans was protected by forts until the American Civil War and Farragut’s demonstrating that with steam engines, the Navy could just bypass the forts, take the city, and starve them out.

          1. Not necessarily, if they were originally placed with sailing ships in mind that were restricted in their movements by the prevailing winds.

          2. It’s a combination of the increased speed of the steam ships and an optical illusion effect humans experience when aiming at moving targets. You have to train people to aim for where the target should be when the shot arrives, and that can mean either aim-to-x-when-target-is-y or training someone hard enough that they develop and instinct for a specific object. But if the latter, similar-but-different objects will not be hit, and if the former, the marks will be wrong for any new technology.

        1. Yeah.

          Since artillery ranges and naval engagement ranges tended to be no more than about a mile throughout this era (often much less), one big part of the mobility limits was that a lot of ships would simply run aground trying to get into certain places in a harbor, river mouth, or other coastal waterway.

          For instance, the famous battle of Hampton Roads, fought between the Confederate ironclad Virginia and various Union warships, was heavily shaped by the fact that many of the ships couldn’t move freely around the estuary; if they moved away from certain shipping channels, they were very likely to run aground.

          The Virginia in particular had to move quite cautiously, because her steam engines were low-powered. They’d been designed for a lighter steam frigate, then immersed in seawater for a while before being salvaged, then having the ship be piled up with hundreds of tons of armor plate. With such anemic propulsion, if the Virginia ran aground, there was every chance that the Confederates would never be able to get the ship moving again under her own power… which is indeed what happened.

    2. In addition to what Ianargent says, I’d say that the second-biggest factor is that fort guns are firing from a fixed platform, while ships move. Until 1900 or so, naval gunnery didn’t come anywhere close to using the entire range of its guns, while land-based artillery generally could, particularly against relatively fragile targets like ships.

      (The biggest factor is the fact that ships were made of wood and forts were made of stone. It wasn’t until steam and shells that ships could even remotely hope to fight forts.) I’ve written a longer history of coastal defenses start at

      1. Well, yes, but there’s a severe balancing factor that made coastal fortifications impossible to employ universally: the cost of cannon. It’s true that a given coastal fort could always be made more secure than navies for a specific investment of resources, but the fact that navies can move mean that they can always potentially concentrate more firepower – if the attacker is wiling to invest in it. Sea batteries would have to disperse firepower since the attacker can always pick and choose the target. Hence, coastal fortifications would always be limited by the opportunity cost of investing the same resources into cannon.

        In practice, they were therefore concentrated at key sites such as major river mouths and ports (often one and the same, of course). This doesn’t mean your statement is wrong, just that the economic side of war makes a big difference in analyzing the overall impact of naval cannon versus fortification cannon.

        1. On third hand however, fact that forts were far less vulnerable meant that even if attacker did manage to concentrate more firepower, fort could reasonably expect to come out ahead in any such exchange with a naval squadron. And ships were extremely expensive to replace, on top of their already high maintenance costs (wood rots in seawater). So navies would still usually avoid combat with forts, and when they had to attack a fort or fortified city, attack would usually either take shape of a blockade, with fleet staying outside the fort’s artillery range, or else navy would simply deliver an army which would disembark some distance away and then besiege the fort the usual way.

  16. Didn’t the lower walls of the star forts made surprise escalade during the night a workable solution to avoid the costly siege ? Since manning the walls of a whole star fort town is costly and prone to errors, and the low walls made escalading a lot less hard.

    This is what almost happened to Geneva during the aplty named Escalade (1602) where only two ladders were used to enter the city, and only fuckups from the assailants prevented them from opening/blasting the main gate.

    1. To do that you’d have to cross the entire open field in front of a fort, without being noticed by sentries, with enough men and ladders to make the assault worthwhile. Keep in mind that the defenders more or less KNOW WHERE YOU ARE or at least where you’re starting from, and that while the sentries don’t have flashlights and flood lamps neither do you. Either you’re stumbling around in the dark, and much more likely to trip or go off course or generally take too long to get to your target; or you’re carrying torches and lanterns and are a lit target for your enemy.

      Possible, yes. Very risk and not at all assured, though.

      1. Night assaults did happen, but rarely. Refreshing my mind on the Siege of Yorktown, the redoubts were cleared by evening assault (on a moonless night, even) per Wikipedia.

        1. Yes, but note that they were attacking outworks in order to get the cannon in range, and it was still considered something of a desperate undertaking.

          1. It appears the fortifications were earthworks, not masonry. All in all (and this is how I meant it) an outlier in military history

    2. Technically they made escalade easier, but the simple answer is FIREPOWER. At this point firearms were so advanced no one dared to approach with ladders.

      1. I recall an episode in the Napoleonic Wars where a French unit recoiled from an escalade against a breach. One of Napoleon’s Marshal’s, exasperated, seized a ladder and went forward. Junior officers rallied and followed, and they argued over possession of the ladder while under fire. In the end the Marshal grudgingly allowed the officers to have the ladder and they successfully assaulted the breach.

        1. Yes, exceptions happen. Our host – Bret Devereaux – recounted an instance of a successful cavalry charge in 2010. In Afghanistan, a Taliban(if I remember correctly) force resisted siege, bombardment, but broke when attacked by cavalry. It was in the Universal Warrior series, about courage.

  17. Very interesting. I wonder about the psychological aspect of warfare at this specific period, though – Bret points out that war is done by humans; in one of the earlier parts, Bret mentions that if the enemy wants to take the town simply for territory, he swaps the administration, but leaves peasants and town-folks alive, so they can still produce taxes, just that taxes go to kingdom B instead of Kingdom A.

    So Genghis Khan deliberatly cultivating a reputation of “surrender, and be treated nicely, but resist, and be treated brutally” was smart tactics for him because it saved time.

    But the 30 years war brought a new element, not just mercenaries, but religion: the enemy wouldn’t just swap administration, but civilians of the “wrong” religion could be slaughtered without remorse (similar to Crusades of Christians not just against Muslim civilians, but also not-Catholic Christians like Konstantinopel for being economic rival to Venice, but Orthodox Christians, or the Albenser), so civilians had good reason to defend their city, too.

    1. In various articles, Bret describes (or links to descriptions of) different forms of/motivations for warfare. Before the appearance of states, massacre was often the goal of war, to gain a larger area (and hence ecological carrying capacity) for the tribe as a whole. Subjugation (or, subjugation by a different lord) became prominent after surplus-extracting states became a thing, but medieval warfare still contained a lot of “agricultural devastation” i.e. killing peasants and burning stuff (buildings, crop fields, orchards) to deny tax income to the other lord.

      There’s also an economic aspect: what is more valuable in that society’s economic setting, labor or land? If labor, then a victor is interested in gaining captives, whether the plan is to leave them in situ and tax them, or to relocate them and sell them. If land, then the victor has little interest in feeding captives (their labor is worth less than the food they eat), instead seeking to seize the land, for use (be that settlement or otherwise) by “their people”, whatever that stands for in context (the range extends at least from “biologically unrelated subordinate tribe member” to “kinsfolk”). In the situation where food is cheap since the human population is instead capped by diseases, yet another result obtains.

    2. > similar to Crusades of Christians not just against Muslim civilians,

      Wasn’t the only occurrence of such during the capture of Jerusalem during the first crusade?

      1. You’re quoting out of context so I’m unsure what you’re about *exactly*, but there were 5 crusades against Hussites alone. They were proto-protestants.

    3. I’m not sure what you mean? Religious massacre was not a new development in the 30 Years’ War, and all of your examples are from before then anyway. If you mean to say that the introduction of religious differences to the Germanies just before the 30 Years’ War meant that armies in Germany were suddenly socially permitted to massacre civilians where previously they had not been, that is also extremely incorrect. Religious tensions did make surrender slightly less likely in that war than in some other wars, but slaughter and rape were a standard part of professional European soldiers’ pay going back into the dark ages and beyond. (most other places around the world too, but I still think maybe you were just talking about armies that could reach e.g. inland Austria?)

    4. The 30-years war actually had a countervailing tendency: The war was eventually fought by professional mercearies; This did not make things any better for civilians (since a good chunk of the motivation of mercearies was to be able to plunder civilians to make money) but it did meant that as the war ground on a certain level of professional courtesy evolved between combatants (especially during sieges) no sense in making a pointless last stand when you can surrender with honours and retreat possibly even with some of the loot.

      Thus all sorts of customs (I wouldnt neccessarily call them “rules”) evolved, about when and how surrender was acceptable, and how much of a show you could make before things got to the “murder everyone” stage. To quote a swedish historian “For some men the war was more of an Opportunity than a Crusade”.

      1. Such customs were in place for a long time. During Croatian-Ottoman wars, a general rule was that crew of a fortress that had resisted bravely *but* had to surrender (due to starvation or something else) before it came down to an assault was allowed to leave the fortress with all weapons and under full honors. To give a few examples I know well, it was done by the Ottomans during Siege of Klis^1, Ottomans made such an offer at Siege of Siget (which was refused by the defenders), and Hungarian-Croatian army also allowed Ottoman defenders of Jajce to leave during Matthias’ reconquest of northern Bosnia. But these were far from the only such examples: *not* allowing it was an exception rather than a rule, and such a measure was usually adopted if defenders (or their leader) had done something perceived as treacherous or dishonorable.

        1^If you don’t know about the fortress, I wrote about it here:
        It is very significant since it is well-positioned to interdict any force trying to reach Split though the passage between mountains of Kozjak and Mosor.

  18. Er, the Hundred Years’ War between England and France was ended by Charles VIII’s grandfather Charles VII and his cannon-masters the Bureau brothers (Jean & Gaspard) victory at the Battle of Castillon in 1453, featuring the decisive use of field artillery, 300 guns. Jean Bureau was the commander at both Castillon and the siege of Bordeaux.

  19. Regarding catapults: would denser projectiles made of metal have been pound for pound more effective against curtain walls than the stone projectiles that were actually used? Or not enough to be worth it?

    1. In previous series, the good professor has noted that metal has historically been stupidly expensive to produce and work, and using it as a consumable is only recently economically POSSIBLE. (with the exception of infantry portable bullets, and even slingers mostly made do with stones unless they needed the slight advantage of lead shot)

      1. The key word is “consumable”. While if shooting at earthwork, the shot will often end up embedded in the target, and if shooting at crenelations, the shot might have enough energy to fall into the fort, in the specific use case of shooting at a stone wall-face with a thick backing, the shot would be almost guaranteed to end up in the ditch at the foot of the wall, from where it might be recoverable, given that enemy firepower is anemic. I don’t know whether a cast iron trebuchet-ball would shatter on impact (not that medieval Europeans could cast iron in the first place), but a wrought iron one wouldn’t. I can imagine such a reusable ammunition being cost-competitive with carting around several tons of single-use carved stone balls (which we know were used, since lucky (or skilled) archeologists have dug up Roman and medieval ammunition depots).

    2. Too expensive and heavy for catapults, but in antique Romans often used lead projectiles for slings. A popular method was to stick your finger into sand and pour lead inside.

      1. That is a field expedient casting method. Prepared slingers used proper moulds, which sometimes included cast messages to the enemy, such as Take That! or Zot! (But in Latin or Greek).

    3. Cast iron has about twice the density of granite or similar stone, so yeah much more effective once you can afford to throw in large amounts at your enemy.

      Lead is almost twice as dense as cast iron, and obviously used for bullets from very early on so must have been relatively cheap. But AFAIK not used for cannon.

      I wonder, would lead cannonballs be sufficiently large to be distorted by the force of the explosion and thus stop being spheres when fired? Or would lead cannonballs be too soft at that size for punching through wood and rock? Any materials / ordinance engineers able to answer?

      1. My understanding is that lead was more expensive than iron, mines being much more rare; Cornwall was famous for having lead deposits, while few places are famous for their iron ore (Roman Aquileia being an exception based on the quality, rather than quantity, of its output; later analysis found this resulted form the local ore containing unusually much nickel).

        In modern (i.e. guncotton) small arms, lead bullets are commonly given a partial or full covering of some copper-based alloy (called a “metal jacket”, as if lead weren’t a metal) because combustion gases passing through the windage (the gap between the bullet and the barrel) and/or friction with the barrel tend to erode the bullet and leave deposits on the barrel. Replacing the gunpowder in an explosive shell and filling it with lead could have been a historical analog (possibly as an alternative to the carronade in giving small ships slightly increased ability to puncture larger ships).

        1. Quite the contrary: lead is the ultimate cheap metal. Lead is a byproduct of silver smelting (from the ore Galena) and so was available as a waste product. Consequently, any use that could be found for it was, thus its use in things like curse tablets, plumbing, bullets, weights, etc. If you needed something heavy, metal and cheap, lead was the go to, because it was cheap. Wikipedia has the “lead was more expensive than iron” line, but cited to a book which does not say that (at least not on the pages indicated) and which honestly wouldn’t be authoritative even if it did, followed by a discussion of powdered white lead cosmetics, which *were* expensive, but were hardly raw cast lead (also, in any event, comparing iron billets in cost to lead ones is missing part of the point, since iron had to be wrought by a smith in a forge to make it useful, while lead could be cast into bullets in a campfire). I’d really need to see an original study with some price data before I’m going to buy that cast lead was regularly more expensive than worked iron.

          My own sense, certainly from the ancient world, was that lead was a super-abundant waste product. Any use it could be put to, it was, because you were going to end up with a lot of it anyway.

          1. A formulary for lead curse tablets recommends using stolen lead pipes from the water system. A discussion of this goes into how it can’t be the cost, so it might be the antisocial nature, or the cold, wet,underground aspect, to lend weight to the curse.

          2. There’s a scene in ‘The Patriot’s where Mel Gibson melts down his dead son’s lead soldiers and makes them into bullets over a campfire.
            I recall much discussion over whether lead soldiers were a likely toy but none over the self casting of bullets.

          3. I can’t cite sources, but my impressions is that soldiers often cast their own bullets because before standardization you had to try various molds until you found one that made balls just the right size for your musket.

    4. I suspect it doesn’t matter much with a catapult, unlike with a cannon. With a cannon the caliber sets a strict limit how on large a ball you can launch and making the ball heavier can make the cannon more powerful. I don’t think it’s even possible to make a ball too heavy that gunpowder can’t launch.

      With a catapult the limit seems to be on how heavy of a missile it can launch. We know the Warwolf could launch a 300 pound rock, no one talks about how many inches it supported. A catapult could launch a 50kg iron ball, or it could launch a 50 kilo rock, just use a bigger sling net. At the speeds a catapult launches it’s missiles aero dynamics probably don’t have significant effect, an iron ball wouldn’t land with a much higher speed than a rock. An iron ball should be able to release it’s energy on a slightly smaller area, but I feel that wouldn’t provide enough advantage compared to the cost.

  20. In nitpicking: I guess with the benefit of hindsight, proto-Spain was formed in 1479, but that wasn’t clear at all at the time. Ferdy & Bella could well have been one of the many political marriages that temporarily form and collapse all the time in history, and Castile & Aragon kept fairly separate administrative structures for another century or two. That said, the absorption of Grenada in 1480-1492 definitely fits this topic – Ferdinand had Italian holdings, and brought over some Italian artillerists to help the Castilian army besiege mountainous Grenadan cities.

    Also, on the theme of strategy game simulations, Civilization V is an interesting example. Civ5 cities are unusually strong and hard to take by series standards. Once Dynamite is researched, the Artillery unit becomes available, and suddenly cities can be outranged, and taken far more cheaply as long as the Artillery is protected. Seems to kind of link up with how in the 1800s, the role of forts changed quite a bit. (Although Civ5’s military side is… abstract. Archers in Rome can shoot at troops in Milan!)

  21. This collection of words:

    “Tonio Andrade (op. cit.)’s description of British gunners tearing apart Qing-dynasty Chinese forts in the First Opium War (1839-42), forts that were designed to resist cannon.”

    has you a verb short of a sentence. I hate to nitpick grammar but I read it like three times looking for the main verb.

    1. Yeah I wondered if that was supposed to lead into a block quote or link or something when I got there

  22. Typo (?): “Tonio Andrade (op. cit.)’s description of British gunners tearing apart Qing-dynasty Chinese forts in the First Opium War (1839-42), forts that were designed to resist cannon.” The first clause of that sentence appears to a verb. Or is a description supposed to follow it?

    You talk about several standard opportunities to surrender in a siege. How did the terms change between those opportunities, or is there anything standard? It would seem that the commander of the defense would prefer to delay surrender as long as possible, even in hopeless positions, so long as he is able to salvage things later. Presumably terms get a lot worse as the attacker gets more leverage. How much worse?

  23. You mention how improvements in artillery changed their capabilities and thus the response of fortifications to them. Would you explain how artillery in 1812 differed qualitatively from artillery in 1512?

    1. Lighter, more mobile, more accurate, as casting improved and standardised parts came in for carriages. Powder also improved, with corning and standard cartridges. Finally, mortars and howitzers came into use (howitzers in the mid 1700s), and shrapnel, making high-angle fire possible.

      1. Don’t forget organisational technology. The armies of the Europe, probably had worked out how to organize a gun crew, for maximal effect a lot better in 1812 than in 1512.
        I once read a story, about the difference of British and Malayan gun crews in the 19th century. The Malayans had a priest with the crew, who spoke a prayer so the gun would not missfire. The British had an NCO, that was tasked with making sure no burning embers remained in the gun. It would not surprise me, if the solution with the priest, was tested in Europe in earlier centuries.

  24. Anyone else on this blog play the old Firefly game Stronghold? Thinking about it in light of this blog post, made me realize that for a supposedly medieval sort of game, the fort designs I often wound up using resembled the Renaissance era stuff, in large part because apparently ahistorically, artillery could be VERY deadly to curtain walls in that game.

    1. I played those games and they fall into the problem a lot of games have in modeling pre-modern sieges, which has that it becomes a shooting contest of archers and artillery, rather than a question of preparing for escalade.

      1. The 2002 Stronghold: Crusader adds “assassins” (they had the decency not to call them ninjas), a perhaps decent proxy for treason or hasty assaults: they are basically useless against experienced human players who habitually post adequate sentries, but I’ve pulled off a covert assault against a human who failed to do so, and multiple campaign levels turn around their use. They are invisible unless within x distance of a hostile unit, can scale walls unassisted, and have enough melee strength to clear archers from towers.

      2. They also have the problem that units have no collision, so chokepoints are pretty useless (except that they make for convenient oil drop zones).

    2. Aside from the problems mentioned by Bret, it looks really odd when attacker focuses his army in a single area, while defenders are completely passive and scattered around the fortress. They don’t react by making sallies or relocating their soldiers near the threatened spots. This kind of game calls for a great AI, not a very bad one.

  25. As I’ve said before, I come for the content and stay for the Alice’s Restaurant references. I also chuckled out loud at both Escalade pictures.

  26. In the (non magical) fantasy novels by K J Parker, specifically the engineer trilogy, a character finds a book that serves as a reference guide to this type of fortification, their construction, how to attack them, how to defend them, how to attack them, and the mathematical formulae required to calculate likely success or failure based on the numbers on each side. I often wondered if such a book existed historically, was the state of the art ever sufficiently stable to codify this knowledge to such an extent?

    1. There were a lot of treatises on this subject. Two of the most famous and definitive ones (as I recall, one for defense, one for attack) were written by the French fortification expert Vauban, who formalized many of the siege techniques Dr. Devereaux discusses (and is indeed name-dropped in the article; see Footnote #3).

      I imagine there wasn’t so much a single book on the subject as an entire slowly evolving library of similar books with overlapping subject material.

  27. “Instead, the Greeks, Macedonians and Romans began using torsion catapults (where the energy is stored in wound-up sinews like a spring).”

    I always find myself wondering if anyone tried to make a scaled-down hand-held torsion bow.

    1. The smallest Roman torsion arrow-shooters are definitely man portable weapons, look to be about as bulky as a modern heavy machine gun or anti-aircraft missile.

      I think going any smaller than the Roman scorpio would be counterproductive. Without modern synthetic rubber you just can’t scale down the twisted cord/rope mechanism much further. Something small enough to shoot arrows would still be clunkier than a bow, and more mechanically complicated – hence more likely to fail on a battlefield – than even a composite bow.

  28. I knew the Spanish crown was profligate with its military at a time when it was endeavouring to consolidate its primacy on both sides of the Atlantic, but I didn’t realize it was that profligate. That combined with the erasure of its former Mediterranean trading empire (maintained by the Sephardim and the Muslims) by the Expulsions, and the fact that the gold, silver and other precious metals they brought over from the Americas which couldn’t go anywhere else, undoubtedly helped in driving the Spanish Empire into hyperinflation, which made Spain such a basket-case that by the time of the French Revolution it became the scene of conflict, rather than exporting it elsewhere.

    Lesson here.

    1. See Paul Kennedy’s “The Rise and Fall of the Great Powers” Chapter Two “The Habsburg Bid For Mastery” both for the fortunes of the Spanish-Austrian dynasty circa 1519 to 1659 and for a look at the changing face of European warfare in that period.

    2. Right, but that is still a span from Expulsions to Peninsular War of what? 310 years? Certainly longer than the US has existed, or the UK as a political unit. So not a precipitous decline, exactly.

      1. Spains decline was, like most of them, staggered a bit, they were probably worse off in the late 1600s than in the 1700s, for instance, until the Napoleonic wars knocked them down again.

  29. Long story short, VERY FEW STAR FORTS CAN BE SEEN IN Poland(11), Russia(10!!!), Ukraine(0?), Hungary(3) etc. Here, they are quite exotic and history buffs often don’t know about them. Different doctrine.

    Eastern Europe lacks natural barriers. This is one of reasons Russia always tries to expand west(others: lack of ports and arable land). In an environment like that, it’s easy to attack but hard to hold ground (Norman Davies – “White Eagle, Red Star”*). Mobility is king. Most of the states mentioned above put much emphasis on cavalry. Polish-Lithuanian Commonwealth had winged hussars, Lisowczycy; hungary had light hussars and more, all except Hungary(to my knowledge) used Cossacks extensively. Tatars and Cossacks were renowned for their horsemanship and cunning tactics. Polish-Lithuanian Commonwealth was notorious for bad roads.

    Add the enemies and distances together and it’s not surprising you needed an army that is very mobile. Using winged hussars as an example: they were highly evolved cavalry, built for power and speed, sacrificing some armor. Their main weapon, lances, were – much like aardvark’s teeth – empty inside, to save weight. This allowed them to regularly outreach pike infantry. Lances were the only standarized piece of equipment they had, they were provided by the king and came in several lengths against different enemies. They were designed for single use and they would just fetch another one from the supply train. They had sabers as a backup weapon and frequently koncerz, a type of large sword like estoc, only for piercing, held in front. The hussars were all volunteers from the wealthy nobility (had to purchase their arms) and would train for the lifetime. The most expensive part was the horse, a special, closely guarded breed with lots of training as well. Crucially, they were able to catch up with light cavalry in short pursuits. Winged hussars proved their worth against Western style armies many times, for example in the Polish-Swedish wars. Swedes call the battle of Kircholm a humiliation(3.5k PLC soundly defeated 10.5k Swedes). Later, Gustavus Adolphus learned that pike&shot stands no chance against cavalry in the open. He only started breaking even and eventually winning when he used SHOVEL, and lots of it(possibly another aardvark inspiration). He also had to abandon countermarch in favor of big salvos – too slow against cavalry charges. And it was still a rocky ride. After a close call where he nearly died, he said if he had a cavalry like that, he would be at Constantinople in 2 weeks. This was several decades before the biggest cavalry charge in history at Vienna.

    No contravallation (earthworks facing outside to combat relief force) was used because cavalry filled that role. Western Europe famously used pike&shot + cannon armies, whereas the East used cavalry&shot + cannons.

    Some more conjecture: hard to sustain big infantry armies in sparsely populated lands with few rivers and towns to squeeze. Cavalry was better at foraging. More mobile armies had fewer cannons and hence no star fortresses.

    There are also videos “How to defend a star fortress” and “How to siege a star fortress”, with nice visualizations.

    An intriguing comment under the video:
    “Similar things happened in China, in Northern China Calvary were prefered but in Southern China Pikes and muskets were prefered. Even armour styles differed from each other.”

    If winged hussars in particular interest you, I recommend the channel. At the moment of this writing, there are 3 more videos about Polish-Swedish war and one focusing on husaria vs Gustavus Adolphus. They also have plans to cover The Deluge, and for series about the Hussite Wars.

    * The book describes the Polish-Russian war of 1919-1921, which is another notable example of cavalry (mobility) power in the East. In a nutshell: the dictator Piłsudski launched an offensive to take Kiev from Russia, and install the Ukrainian leader Semen Petlura. It didn’t work out (not enough Ukrainian support for Petlura; disagreement between Polish leaders Piłsudski and Dmowski). Poles started a retreat, and they suffered HEAVY losses on the hands of 1st Cavalry Army led by Budyonny. Really, he was like a recurring villain. Miraclously, Poles turned this around when they got back to Warsaw. Norman Davies attributes it to a bold, risky battle plan and high cohesion due to nationalism and catholicism, plus discord among bolshevik leaders including young Stalin. Poles are right leaning since basically forever. Fun fact: this was the first war where aircraft was used (reconnaisance planes on Polish side, very successful). Ladies check out photos of young Stalin – stunningly handsome.

    1. Uh… nitpick: You say “this was the first war where aircraft was used.”

      Aircraft were used extensively by all sides of World War One, which took place before the Polish-Soviet War, and indeed made the Polish-Soviet War possible. Without World War One (including its early use of air power), there would have been neither an independent Poland, nor a Soviet Union to invade them.

      Furthermore, aircraft were also used in some other wars fought before 1914, on a limited scale, as I recall.

      1. Depending on your definition of “aircraft,” more than a century before that. The French used hot air balloons for spotting as early as the Battle of Fleurus, 1794, and they were used extensively during the ACW by artillery crew. The first powered, heavier-than-air aircraft were used in the Italo-Turkish War, 1911-1912.

    2. Hungary was during the 17th century Ottoman wars stuffed with star-forts and bastion-fortified cities. Not as densely as the Netherlands, and many older castles remained in use, and few of them survive, since after the Habsburgs regained the kingdom from the Ottomans they were more of a threat than an advantage.

      Here are the Ottomans sieging Érsekújvár:

      Here the Holy League (Habsburgs, Bayer, various other German states and Hungarian loyalists) sieging Ottoman-held Buda:
      The city walls are of earlier pattern, but the western style of methodical siege is in use.

      Here is Győr, an old city defense upgraded to italian-style bastions and extensive outworks:

      Here is Petrovaradin (Pétervárad), now in Serbia, but in the 18th century it was on the Hungarian-Ottoman frontier, so it has an extreme amount of fortification.

      1. To add to that, a lot of those fortifications were destroyed in the decade(s) of their capture. The Habsburgs (and, almost around the same time for similar reasons, the French) expended enormous amounts of gunpowder blowing up fortifications outside the border regions. Following the failure of the Rakoczy revolt (1711), this process sped up considerably.

        So it’s not that Easter Europe was bereft of forts. It’s that only forts that either had a military use for the dominant power (eg, were on the border), or had absolutely no use at all (eg the inevitable rebellion/uprising can’t use it) remain to this day.

        Which is somewhat similar to what happened to forts in western/southern Europe too. It used to be lousy with castles, star forts, fortifications, etc, but as soon as those lost their military value, most of them were demolished. The ones you see now are an exception.

    3. Balloons are aircraft. The Union army in the American Civil War had barges they sent up and down the Potomac, and then had a guy with binoculars go up in a hot air balloon.

      Confederates soon learned to hide from them, so they never stopped. Forcing them to take routes invisible to the balloons wax valuable in itself.

  30. From this comment: “That said, it is important not to overstate this; field works in the civil war mostly remained breastworks (that is, built above ground) rather than trenches (though these were still used in sieges)”

    I am not entirely certain how accurate that was in the Civil War. It seems that past Spring of 1862, soldiers got very good about making fortifications, often daily in a near-imitataion of Rome. Trenches were not always possibly depending on the ground, and they would certainly have been shallow until there was time to dig them out, but they apparently did get employed quite frequently and not only in clear sieges, time permitting. And of course, Civil War fortificaitons were used, as often as not, to gain an advantage in a potential battle, and ideally, prevent a siege situation from ever actually occurring (as in the case of Charleston or Richmond).

    1. Lee, when he took over command of the Army of Northern Virginia, quickly earned the moniker “General Spade” for his instance that and unit not actively on the march be entrenching in position.

  31. On catapults in chess: Xiangqi, aka Chinese chess, has a catapult piece (well, one player has a catapult, the other has a cannon- pieces are traditionally labelled with similar but not identical characters so they can be told apart by means other than colour).

    On Fort McHenry: The heavy mortars the British used had to be mounted on specialised ships known as bomb-vessels. As these were very strongly built to cope with the recoil, after they ceased to be militarily useful they became popular as polar exploration vessels. One such vessel which took part in the bombardment, HMS Terror, was used in the Ross Expedition to the Antarctic (thus having a volcano named after it) before being lost with the Franklin Expedition to find the Northwest Passage.

    On escalades: The anniversary of the failed 1602 attempt to take the city of Geneva by a combination of stealth and escalade (a small unit going over the walls at night to open the gates) is still a festival in the city. Celebrations include smashing chocolate cauldrons while shouting “thus perish the enemies of the Republic!” then eating the bits of cauldron and the marzipan vegetables it contained.

    (According to legend one of the first Genevans to notice the attack was a housewife living above the gate who dropped a cauldron of boiling soup on the attackers).

  32. I just wanted to say that my heart skipped a beat when I saw Bourtange. I recognized it immediately- I’ve been there and it’s really lovely. Also they might have the most charming Christmas Fair anywhere.

  33. Hello Prof, really enjoying your fortification articles. The ACW fortifications were really interesting. Never knew they had those bunkers flat in the ditches.

    I’d like to ask you on a minor quibble, however – didn’t the later phase of the HYW already see massed artillery use before 1494? The siege of Orleans certainly saw artillery employed with significance, both by the French in the city proper and the English in the Tourelle boulevard. And even if we don’t view the French artillery of the HYW as a organized artillery train, the Burgundian artillery train under Charles the Bold would seem to hold up to Charle VIII’s siege trains – way before the Italian Wars.

    Not that I’m disagreeing with the general direction of this great article – Mordano, Fivizzano, Monte Fortino and Monte San Giovanni certainly fell in short, brutal order in which artillery certainly played a role, and they certainly caused quite a shock (as did French brutality), and I recognize that you’ve already stated that this article somewhat simplifies things, and alreay mentioned that some old fortifications certainly were overhauled to defend against an artillery train… Just being a tad… pedantic, s’all.

    And another question if I may – were there significant changes in ‘How to assault a bastion fort?’ manuals? Pararell lines, counter-battery, breaching battery, communication trenchs and so basically seem similar, but say, the 1697 siege of Ath seems radically different from Badajoz 1812. I understand each siege has very specific circumstances – but were there methodical changes before the advent of shell and shrapnel? Was just curious because Napoleonic sieges seem to end with storming the breaches a LOT more than 17th century wars. Don’t know the exact statistics, so I may be in the wrong…

    Again, thank you for the great articles!

  34. While its important to stress that most cannonballs did not explode, (but were roundshot) there were various attempts with various efficiency explosives (the “cartoon bomb” is an example of this, a cannonball filled with gunpowder and given a fuse, obviously fairly complicated, and AFAIK, usually launched by mortars or howitzers rather than “proper” cannon) there were also various inciendary projectives (other than heated show) some of which, IIRC basically involved a big glob of tar and wood or similar, the swedish term is “fyrboll” (more or less “fireball”) and there is an example on the Marine Museum:

  35. First of all – really enjoying the fortification series. The ACW fortifications were especially interesting – never knew about those bunkers flat in the ditches. Really looking forward to the next installation now.

    Minor quibble, though. Didn’t the later phases of the HYW and such already see massed siege artillery? Certainly the siege of Orleans(1429) is famous for artillery usage, both by the French in the city and the English in the Tourelles boulevard. And even if one doesn’t view the haphazard artillery parks as a properly organized siege train, the Burgundian train under Charles the Bold would seem to quite hold up to Charles VIII’s train, way before the Italian Wars.

    Not that I’m disagreeing with the general gist of the article – in spite of predating artillery usage such as Caravaggio(1448), the Italian response to the short, brutal sackings of Mordano, Fivizzano, Monte Fortino and Monte San Giovanni certainly seems to be one of shock – though I somewhat suspect the shock factor came from the ‘more brutal’ warfare of the ultramontanes as well. The Italians had artillery of their own, after all, and waged siege warfare against the French too. I totally get that you’re trying to set up a general direction of the evolution of fortifications, and you’ve already mentioned the hasty retrofit stuff going on before the trace italienne really sits in. Just being a tad… pedantic, s’all.

    Also, a question if I may – were there significant doctrinal changes in ‘how to assault a bastion fort?’ Most of the main components seem the same – circumvallations, parallel lines, communication trenches, breaching battery, counter battery, so on… but looking at the details, the 1697 siege of Ath seems quite different compared to Badajoz 1812. I understand each and every siege has very specific circumstances, but were there a sort of doctrinal re-thinking? Was curious because Napoleonic sieges seem to end with the hope storming the breaches a lot more than settling on terms after a protracted siege, like the 17th century. Maybe something to do with the general trend of more field battles? Of course, could maybe just plain old misconception on my side.

    Again, thanks for the series and this blog! Really enjoying the content!

    1. I expect part of it simply being that Napoleonic field armies were much larger, so the men were more expendable, so to speak.

  36. Very interesting. I always learn something from your articles. BTW I grew up about a mile from Fort Brockhurst, one of “Palmerston’s follies”. These were a ring of artillery forts built around Gosport and Portsmouth, in the UK, in the 1860s to protect the Royal Navy from a French invasion. They are still pretty much intact and some are museums. One of them was used as the HQ for operation Overlord.

  37. Someone else may have said this. I’m not sure. That said…the Theodosian Walls managed to resist the cannon. The city still fell, but the massive numbers of the enemy had a lot to do with that, and while the Theodosian walls were damaged they weren’t breached. It’s notable that the walls were still being used until the 19th century.

    Theodosius’ engineers were never matched.

  38. So! A cool aside about explosive shells!

    In China, explosive shells *predate* cannon. The Siege of Kaifeng (1232-1233) is to my knowledge the first battle where *both* sides used gunpowder, most famously the Jin using explosive shells that were launched via trebuchet, and from their official reports (trans. Turnbull 2003):

    “Therefore the Mongol soldiers made cowhide shields to cover their approach trenches and men beneath the walls, and dug as it were niches, each large enough to contain a man, hoping that in this way the troops above would not be able to do anything about it. But someone suggested the technique of lowering the thunder crash bombs on iron chains. When these reached the trenches where the Mongols were making their dugouts, the bombs were set off, with the result that the cowhide and the attacking soldiers were all blown to bits, and not even a trace being left behind.”

    My read of the chain of events is that the part of the kit that traveled westward was the solid-shell cannon setup as a whole concept, and having shells that could survive being launched via gunpowder was still beyond what even the various Chinese states could pull off until quite a bit later. So a bit pedantic, but hey that’s why we’re here.

    I did have a question about the types of siege you’re describing here – you describe the course of events where an attacker is at an objectively high confidence of success. What’s the course of events when that confidence is lower? Do we have negotiations that vary considerably or is it basically just variations on “the defender surrenders or gets slaughtered”? Like do the negotiation terms get more favorable to the defender if a relief army is a credible threat, do attackers just have to peel off the attack because they made the calculation that they’d get a quick surrender but they did not in fact have the budget or timeline for a protracted siege, that sort of thing?

    1. Ah, there’s an important distinction here between grenades and bombs on the one hand and explosive shells on the other hand. Grenades and bombs are, as you note, very old. The problem here is not “how do I fill an iron ball with black powder.” The problem is “how do I fill an iron ball with black powder in such a way that I can fire it out of a cannon, not have it explode in my cannon, and then have a fuse on it which will explode the iron ball at a precise height a mile or so away from me directly over a target.”

      The key developments here are in fuses and ballistics, not hollow iron balls with black powder in them.

      1. Yep! I just think its neat that the Jin had the timing at least somewhat down during that era, and that to my knowledge the technique was not spread westward (and for that matter I don’t think much used in the East Asian theatres once gunpowder-propelling-solid-shot was more refined).

        And cool to me at least was that this predates the counterweight trebuchet in East Asia – first used in the Battle of Xiangyang in 1273, when some Middle Eastern engineers working for the Mongols built some and they proved to be a rather decisive change given that the city surrendered shortly thereafter (and this is generally considered the most decisive battle of the Song conquest).

  39. Brett:
    I’m way-y-y late to the party, but I’m sure you won’t be seeing this for a while anyway . . .
    Caption for trebuchet: the ropes handing down > hanging
    we can’t achieved much if we’ve rendered our walls save > achieve . . . safe
    defenders fire down > defenders to fire
    When places at the corners > placed
    It is of part and parcel > delete of
    enemy attack either from > delete either ? (or finish incomplete compound: either…or)
    One that first parallel > Once

    1. btw, Bret regarding your Escalade “joke” . . . don’t you know you’re not supposed to laugh at a pun? The culturally accepted form of appreciation is a nice prolonged “gro-o-oan.”

    1. Neat! Though of course I must note he has in fact produced a tension-assisted sling, rather than a trebuchet (multiple rotations used to store up energy makes it a sling in my book). I wonder if he could get better results using torsion instead, as the Romans did.

      It also seems relevant to note that in the choice between launching a very small projectile very fast and a more massive, larger projectile somewhat slower artillery generally would rather do the latter. The reason is that drag (= air resistance) increases, if I recall correctly, by the square of the velocity of the object so the faster you go, the more energy – much more – you lose to drag. Since the goal isn’t impact speed but impact energy, it thus generally makes more sense to deliver that energy by adding mass than by adding velocity, beyond a certain point.

      This was one of the great advantages of carronades, a kind of 18th century cannon which functioned something like a sawed-off shotgun firing a solid slug. Shortening the barrel allowed for firing a heavier shot at lower velocities, thus resulting in higher delivered impact energies, albeit at substantially shorter range (but given the accuracy of the weapons, the theoretical longer range of long guns was essentially lost because no engagement happened at those ranges).

      1. Except that carronades were just the very short range armament. With good crews, long guns could could start hitting at half a mile or more. Carronades were for the last hundred yards. Apart from the heavier ball, they also were quicker to load and fire, as they were mounted on slides rather than carriages.

  40. You know, China having earthworks for fortress (no stone handy?) and the observations above about the effect on states casts some light on Chinese history.

  41. I think it is worth to mention, that there also was a lot of intermediate fortification efforts between period of pure medieval style of castles and trace italienne. E.g it did not happen over a day. It was some kind of evolution for this.
    At first the existing castles were tried to continuously upgrade to resist gunpowder arms: adding special constructions like barbikans, rounded bastions and so on

    1. It was worth a mention. Which is why I mentioned it:

      “Now I should note that the initial response in Italy to the shocking appearance of effective siege artillery was not to immediately devise an almost entirely new system of fortifications from first principles, but rather – as you might imagine – to hastily retrofit old fortresses.”

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