Collections: Phalanx’s Twilight, Legion’s Triumph, Part IIa: How a Legion Fights

This is the first part of the second part of our four? four part¹ look (Ia, Ib, IIa, IIb, IIIa, IIIb, IVa, IVb, IVc, V) at the great third and second century BC contest between the Hellenistic armies of the heirs of Alexander and the Roman legions. Last time, we looked at the Hellenistic army as a complete system, incorporating not just the famed Macedonian sarisa-phalanx, but also light and medium infantry and a decisive cavalry-striking force. This week, we turn to the Romans to look at how the Roman legion of the Middle Republic is structured and its tactical system. Then, for the second half of this part (next week) we’re going to zoom out a bit and look at some of the operational and strategic level advantages the Roman legion enjoys.

And here it might be a good time to refresh those terms. When we talk about tactics, we mean the methods used to win battles at the lowest layer of military analysis. Whereas, when we talk about strategy, we are talking about the upper-most layer of military analysis, which is concerned with end goals (‘ends’), the methods to reach those goals in the big-picture-abstract (‘ways’) and the resources required to do so (‘means’). In between these two layers is operations, which is where all of the thorny problems of moving large armies over vast distances come in: logistics, long distance maneuvers, coordination of forces and so on. To simplify a bit, tactics is the how of war, operations is the where and strategy is the why: tactics is how you fight a battle, operations where you fight that battle and strategy is why you fought that battle in the first place (for more on these terms, you can consult our handy Military Terminology Glossary!)

This week, we’re looking primarily at Roman tactics, because the interaction of the Roman tactical system with Hellenistic armies, I will argue later, gave the Romans a fairly clear edge, especially in the second century once the full system seems to be in place. Whereas Hellenistic armies aimed to win with a decisive cavalry strike on the flanks, Roman armies were fundamentally attritional, aiming to win by grinding down the center of the enemy army. As we’ll see, that attritional approach influences tactics, but it also impacts weapons. The interaction of tactics and weapons itself is a huge topic, but fortunately, we’ve already discussed the key Roman weapons involved, the pilum heavy javelin and the gladius Hispaniensis, so I’ll be referring back to those posts a bit here.

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Of Combined Arms and Men

The basic building blocks of Roman armies in the Middle Republic are the citizen legion and the socii alae or ‘wing.’ A ‘standard’ Roman army generally consisted of two legions and two matching alae. but larger and smaller armies were possible by stacking more legions or enlarging the alae. We’re not nearly so well informed as to the structure of the alae of socii (the socii being Rome’s ‘allied’ – really, subject – peoples in Italy), except that they seem to have been tactically and organizationally interchangeable with legions. Combined with the fact that they don’t seem archaeologically distinctive (that is, we don’t find different non-Roman weapons with them), the strong impression is that at least by the mid-third century – if not earlier – the differences were broadly ironed out and these formations worked much the same way.² So, for the sake of simplicity, I am going to discuss the legion here, but I want you to understand (because it will matter later) that for every legion, there is a matching ala of socii which works the same way, has effectively the same equipment, fights in the same style and has roughly the same number of troops.

With that said, we reach the first and arguably most important thing to know about the legion: the Roman legion (and socii ala) of the Middle Republic is an integrated combined arms unit. That is to say, unlike a Hellenistic army, where different ‘arms’ (light infantry, heavy infantry, cavalry, etc) are split into different, largely homogeneous units, these are ‘organic’ to the legion, that is to say they are part of its internal structure (we might say they are ‘brigaded together’ into the legion as well). Consequently, whereas the Hellenistic army aims to have different arms on the battlefield in different places doing different things to produce victory, the Roman legion instead understands these different arms to be functioning in a fairly tightly integrated fashion with a single theory of victory all operating on the same ‘space’ in the enemy’s line.

And you may well ask, before we get to organization, “What is that theory of victory?” As we saw, the Hellenistic army aims to fix the enemy with its heavy infantry center, hold the flanks with lighter, more mobile infantry (to protect that formation) and win the battle with a decisive cavalry-led hammer-blow on a flank. By contrast, the Romans seem to have decided that the quickest way to an enemy’s vulnerable rear was through their front. The legion is thus not built for flanking, its cavalry component – while ample in numbers – is distinctly secondary. Instead, the legion is built to sandpaper away the enemy’s main battle line in the center through attrition, in order to produce a rupture and thus victory.

To do that, you need to create a lot of attrition and this is what the manipular legion is built to do.

The legion of the Middle Republic is built out of five components: three lines of heavy infantry (hastati, principes and triarii), a body of light infantry (the velites), and a cavalry contingent (the equites). Specifically, a normal legion has 1200 each of velites, hastati and principes, 600 triarii and 300 equites, making a total combined unit of 4,500. Organizationally, the light infantry velites were packaged in with the heavy infantry (Polyb. 6.24.2-5) for things like marching and duties in camp, but in battle they typically function separately as a screening force thrown forward of the legion.

So to take the legion as an enemy would experience them, the first force were the velites. These seem to have been deployed in open order in front of the legion to screen its advance. These fellows had lighter javelins, the hasta velitaris (Livy notes they carried seven, Livy 39.21.13), no body armor and a ‘simple headcovering’ (λιτός περικεφάλαιος, Polyb. 6.22.3), possibly hide or textile; they also carried a smaller round shield, the parma, and the gladius Hispaniensis for close-in defense (Livy 38.21.13). These are, all things considered, fairly typical ancient javelin troops, aiming to use the mobility their light equipment offers them to stay out of close-combat.

Behind the velites was the first line of the heavy infantry, the hastati. These fellows were organized into units called maniples (lit: ‘a handful’) of 120, which in turn are divided into centuries of 60 each. The maniples are their own semi-independent maneuvering units (note how much smaller they are than the equivalent taxeis in the phalanx, this is a more flexible fighting system), each with its own small standard (Polyb. 6.24.6) to enable it to maintain coherence as it maneuvers. That said, they normally form up in a quincunx (5/12ths, after a Roman coin with the symbol of five punches, like on dice) formation with the rear ranks, as you can see above.

The hastati (and the principes, who are equipped the same way) have the large Roman shield, the scutum, two heavy javelins (pila), the gladius Hispaniensis sword, a helmet (almost always a Montefortino-type in bronze in this period) and body armor. Poorer soldiers, we’re told, wore a pectoral, wealthier soldiers (probably post-225, though we cannot be certain) wore mail. That is, by the standards of antiquity, quite a lot of armor, actually – probably more armor per-man than any other infantry formation on their contemporary battlefield. That relatively higher degree of protection – big shield, stout helmet (Montefortino’s in this period range from 1.5-2.5kg, making them unusually robust), and lots of body armor – makes sense because these fellows are going to aim to grind the enemy down.

Note that a lot of popular treatments of this assume that the hastati were worse equipped than the principes; there’s no reason to assume this is actually true. The principes are older than the hastati, but the way to understand this formation is that the velites are young or poor, whereas for the upper-classes of the infantry (probably pedites I-IV) after maybe the first year or so, they serve in the heavy infantry (hastati, principes, triarii) based on age, not on wealth (and then the equites are the truly rich, regardless of what age they are; the relevant passage here is Polyb. 6.21.7-9, which is, admittedly, not entirely clear on what is an age distinction and what is a wealth distinction).

We’ve discussed the combat width these guys fight with already – somewhat wider spacing than most, so that each man covers the other’s flanks but they all have room to maneuver. It seems like the standard depth in the Middle Republic was either base-3 (so 3 deep on close order, 6 deep for ‘fighting’ open order) or base-4 (so 4 and 8). Even in open-order with the maniples stretched wide (possibly by having rear centuries move forward), there would have been open intervals (10-20m) between maniples, which reinforces the role of a maniple as a potentially independent maneuvering unit – it has the space to move.³

Behind the hastati are the principes, with the same equipment and organization, slightly off-set to cover the intervals between the hastati, with a gap between the two lines (we do not know how large a gap). These men are slightly older, though not ‘old.’ The whole field army generally consists of iuniores (men under 46) and given how the Romans seem to like to conscript, the vast majority of men will be in their late teens and 20s. So we might imagine the velites to be poorer men, or men in their late teens (17 being the age when one become liable for conscription) or so, while the hastati are early twenties, the principes mid-twenties and the handful of triarii being men in their late twenties or perhaps early 30s. The positioning of the principes isn’t to spare older men the rigors of combat, but rather to put more experienced veterans in a position where they can steady the less experienced hastati.⁴

Finally, behind them are the triarii, who trade the pila for a thrusting spear, the hasta, the Roman version of the Mediterranean omni-spear. These men are, as noted, the oldest and so likely the calmest under pressure and thus form a reserve in the rear. The three-line system here is what the Romans call a triplex acies (‘three battle lines’). This wasn’t the only way these armies engaged and they could sometimes be formed up into a single solid line, but the triplex acies seems to have been the standard. We don’t know exactly how deep such a formation would run, but we have fairly good evidence that a legion might occupy a space around 400m wide (with some variation), meaning a whole Roman army’s core heavy infantry component (the two legions and two alae) might be some 1.6km (about a mile) across.

The equites, while organic to the legion organizationally, will be tactically grouped in battle to form cavalry screens on the edges of the army, not as a grand flanking cavalry ‘hammer,’ but as flank-protection for the advancing infantry body (as a result, they tend to fight more cautiously). The equites in this period are heavy cavalry, with armored riders (after c. 225, that would be mail), using a shield and a hasta, along with a gladius as a backup weapon and thus serving as ‘shock’ cavalry. Roman cavalry, if we look at their deployments, is generally ample in numbers, but the Romans seem to have been well aware it wasn’t very good, and sought allied cavalry (especially non-Italian allied cavalry) whenever they could get it. But the cavalry, Roman or not, was almost never the decisive part of the army.

Polybius tells us that the socii supplies more cavalry than the Romans and implies that there was a standard rule of three socii cavalrymen to every Roman equites, while socii infantry matched Roman infantry numbers (Polyb. 6.26.7). Looking at actual deployments though, we see that the socii tend to outnumber the Romans modestly, on about a 2:3 ratio, with socii cavalry only modestly outnumbering Roman cavalry.⁵ Consequently a normal Roman consular field army (of which the Romans generally had at least two every year) was 8,400 Roman infantry, around 12,600 socii infantry, 600 Roman cavalry and perhaps a thousand or so socii cavalry, for a combined force of 21,000 infantry (c. 5,000 light 16,000 heavy, so that’s a lot of heavy infantry) and 1,600 cavalry. That somewhat undersells the cavalry force the Romans might bring, as Roman armies also often move with auxilia externa (allied forces not part of the socii), which are very frequently cavalry-heavy (especially, after 203, that really good Numidian cavalry).⁶ By and large, it’s not that the Romans bring a lot less cavalry (as a percentage of army size), but that Italian cavalry tends to perform poorly and the as a result the Romans do not built their battle plans around their weakest combat arm.

Perhaps ironically, the Romans used their cavalry like Alexander and Hellenistic armies used their light infantry: holding forces designed to keep the flanks of the battlefield busy while the decisive action happened somewhere else.

Roman Fighting

With our units in place, we can now walk through the intended engagement pattern of the legion (keeping in mind that it isn’t operating alone, but likely has another legion deployed on one of its flanks, and then this two-legion formation has two alae of socii, similarly organized, on their flanks). First, we’re going to look at it from the Roman perspective to get a sense of what happens when, and then we’re going to pivot and look at what it would be like to be at the business end of this system to see how its attritional system works.

The first thing is that the Roman army almost certainly advances into contact; the Romans tended not to wait to receive assaults (to be fair, neither did Hellenistic armies or earlier Greek hoplite phalanxes either) but instead looked to advance into contact. The velites go forward; they have no officers with them (their officers, organizationally, are the centurions who are back with their maniples) and so we shouldn’t imagine much in the way of formation here, which is fine because the style of fighting they employ is not formation based. With seven lighter javelins (the hasta velitaris), the velites can continue skirmishing over longer periods as the battle develops.

In practice, the velites serve a few roles in this initial phase. On the one hand, of course, the velites can skirmish an advancing line of enemy infantry, throwing their lighter javelins while staying out of reach. If the enemy charges the velites in response, because their equipment is lighter and they are the younger men, they can easily fall back faster to the safety of the hastati. An enemy that has broken formation to pursue the velites which then slams face-first into the hastati while tired and out of formation is going to have a very bad time. Consequently, the velites can harass enemy infantry pretty readily, falling back as needed.

On the flipside, the velites also serve a key screening function. If the enemy has skirmish or missile infantry themselves, they could present the advancing Roman heavy infantry with the same problem: advance slowly and get harassed by javelins and arrows or charge – breaking out of formation to do it – and get torn up by supporting heavy infantry. But with the velites out in front, they absorb that fire. While in video games it is often really easy to have archer units or javelin units simply fire over low-value units to hit high value units behind them, on actual battlefield where troops are limited to what they can see with their Mark-One Eyeballs at head-height, a screening force of light infantry in front like this can essentially shield the advancing heavy infantry. Meanwhile, because the velites are not in close-order (thus, lots of open space for arrows or javelins or sling bullets to miss into) and have shields, they make poor targets for massed missile fire.

Consequently, the velites can effectively ‘deliver’ the rest of the legion intact against an enemy with their own light infantry screen. Now of course, Hellenistic armies don’t have a forward-thrown light infantry screen; their light infantry is deployed on the flanks. Once again, video-game tactics here are a poor guide. Often in something like a Total War game, an archer unit deployed on a flank can cover most of the army’s line. But real armies are a lot bigger. A single legion probably occupies around 400m of frontage, recall – whereas effective bow range fades out around 200m in most cases. So a unit of archers, deployed on the flanks of a legion would struggle to hit targets at the center of that legion – and a normal Roman army is four legions wide, so archers on the flanks of that formation are way out of range of the formation’s center.

Once the enemy has closed enough to press the velites, they retreat through the intervals of the hastati. Meanwhile, the maniples of the hastati probably shift to their standard combat spacing and depth, filling most but not all of the open intervals. The remaining 10-20m spaces between the maniples gives the rest of the velites somewhere to go, which is important: having your own light infantry pushed back into a heavy infantry formation can disrupt it, but here there’s no problem as there are lanes ready for it already. The hastati then hurl their pila and charge into close-combat. With only two pila, this isn’t going to be an extended barrage⁷ but a ‘throw-and-charge’ quick sequence of shocks against the enemy front line.

The hastatus‘ kit in turn demands a particular sort of fighting once he comes into close contact: after all, he doesn’t have a 2.5-3m long spear, but rather a c. 75-85cm sword. Now in practice the fighting distance isn’t as long as that difference implies, since the spear isn’t gripped all the way to one end the way a sword is, but fighting with the spear carried overhand it might be held around the midpoint (so 125-150cm of reach) or perhaps choked up a bit closer to the tip, whereas the Roman has just their 60-65cm of blade length. Consequently, the Roman soldier has to advance through the striking range of the spear to get into range himself, which of course is part of what the large, curved scutum – the Roman shield – is for, since it covers basically the whole body of the man behind it.

But of course once in close at sword-striking ranges, the advantages shift to the Roman: his versatile cut-and-thrust sword is made for this, his large shield makes it much harder for his opponent to land a good hit (or see what the Roman’s sword is doing) and his heavier armor makes it less likely that hit will be disabling or fatal. Given this fighting style, it seems no accident that where Greek sources often extol a kind of courage (andreia) sometimes described as ‘passive’ courage (holding position and standing impassively in your assigned place), the Roman equivalent – virtus – is an aggressive, borderline reckless courage (mixed with drive, ambition and energy) that has to be restrained by the other key Roman martial virtue, disciplina. You can get a sense of this different, more aggressive ethos from a Roman military oath Livy (22.38.4) recalls, that the soldiers were made to swear “not to abandon their formation, neither for fear or flight, but only in order to pick up a weapon, or strike an enemy, or save a fellow citizen.” Both “I saw my buddy Gaius was in trouble” and “I saw that foe was focused on someone else and left his left side open” are valid reasons to move out of position in formation, at least for a moment.

Now you may be imagining that those intervals between the maniples are going to be a problem. I think Michael Taylor has actually done a pretty good job showing that the intervals between the maniples were never fully close up – the Romans in this period never formed a single solid line, but fought a series of 120-man maniple-blocks. But the 10-20m wide intervals are also hardly inviting for the enemy. Attacking through them means flanking your own formation (as Romans from your right and left dash out of formation “in order to strike an enemy”) and if you do get through, you are going to run headfirst into the next line of Roman infantry, the principes. The other factor here is probably the velites; while they’re not close-combat infantry, they do have swords, the same gladius Hispaniensis as everyone else (Livy 38.21.13) and serviceable if smaller shields. We’re not told this, but it seems almost certain to me that the velites are probably in these intervals (probably still throwing javelins) as well, fluidly filling the gaps without getting ‘stuck in’ in the front.

Now there are certainly battles where the hastati proceed to win the battle, often because the impact of that initial onset overwhelms the enemy. Livy sometimes briefly mentions (e.g. Livy 8.16.6)⁸[ these sorts of battles as being won clamore atque impetu primo, “at the first shout and onset.” But if the hastati‘s onset doesn’t trigger morale collapse and flight, the attritional structure now takes over: the hastati fall back through the next line, the principes, who then engage.

This rank-exchange procedure prompts a lot of incredulity from students, but it is abundantly clear that this is how the Roman legion worked. And it isn’t so implausible in any event. First, remember that these maniples do have the necessary command structures: two NCOs (the centurions) to make the decision to fall back and coordinate the movement, as well as their own standard and standard-bearer to reform around if necessary (centurions, at least by the late Republic and the imperial period, also wear helmets with very distinctive transverse crests, making it easy for soldiers to find their centurions in the chaos). For an enemy, chasing the hastati also poses the same problems as chasing the velites did – there’s another line of entirely fresh, well-formed heavy infantry behind them, so if you break ranks to maximize the casualties the hastati take in withdrawal, you’ll end up cut to pieces by the principes. Finally, of course, the velites are not gone, so that screening force can also cover the withdrawal. That’s not to say it was always so orderly – one has to imagine many times the hastati just came apart. These are, after all, some of the less experienced men in the army. But even if they just collapse, the intervals between the maniples of the principes are going to funnel them together again, where their centurions can get ahold of them, reorganize them around the standard, without disrupting the principes.

The principes, you will recall, have exactly the same equipment as the hastati and so they now engage the same way: another barrage of pila, another clamor (the war-cry), another sudden onset of gladii, their intervals still full of velites (and maybe the hastati). You can, I hope, start to see how casualties and wounds are beginning to stack up for the enemy. Generally, it seems like the expectation was that the principes were the ‘battle winners,’ at least for tough fights. Having matters ‘go to the triarii (ad triarios venit) meant things were going badly and Plautus – a Roman comedic playwright who wrote during the Second Punic War (and who is hilarious) – even jokes about how the triarii never do anything (Plaut. Frivolaria frag. 5 – that’s right folks, we got a fragment of old Latin into this post).

That said, if the principes can’t get it done, the triarii in the rear, composed of the oldest and most experienced men can either provide a nucleus for the whole army to try one more time to break the enemy lines or else cover a fighting withdrawal. It is possible that the triarii‘s longer persistence with the hasta over the pilum reflects this need for these guys, more than anyone else, to stand their ground or die trying. We’ll come back to the triarii, but I think their role as the army’s backstop may⁹ have some explanatory power for why Pyrrhus in particular really struggles to deliver a sufficiently decisive defeat to Roman armies: it’s hard to ‘run up the score’ once you are winning if the enemy has a built in ‘die-so-everyone-else-can-get-away’ component.

One Very Bad Day

And now let’s shift perspectives to that enemy front line. You’ve formed up in your fighting order and begun to advance and first a cloud of light enemies (the velites) move up against you. Behind them, you can vaguely see the main Roman body, but not in much detail yet. Instead, you are treated to shower of lighter javelins; these only mass around 250g or so, but some of them are bound to catch a face or an unarmored leg and bring someone down or get stuck in a shield. The damage is probably minimal, but what the velites are doing is already wearing you down: you are now, physically and mentally ‘in combat,’ with weapons flying and adrenaline running (whereas the Roman heavy infantry are not!). The velites don’t need to inflict casualties at this stage to have an effect: they’re inflicting friction (in the Clausewitzian sense, drink!) and that is enough.

As you approach the velites, they scatter back to their lines and now the first real trial comes: when you are about twenty meters out from the enemy line, a storm of those heavy pila come in, thick and all at once. Each one masses around 1.3kg (just short of three pounds) so even if the tip doesn’t bite, one of these things clanging off of armor or a shield is going to hurt, the impacts stagger men near you as you struggle to keep formation (and for a Hellenistic army, get and keep those sarisa-points down). The impact of the massed volley, especially against close-order infantry with tight fighting-width, is going to be chaotic as some men are killed, others disabled, still more suddenly staggered. The volley is followed almost immediately by the on-rush of the hastati. These guys don’t have a long spear for keeping you at a distance, they’re all brandishing swords and aim to get in close, using their large body-shields to absorb any blows you might throw while they get right up in your face, where their swords can stab and slash viciously over or under your shield. These hastati are aggressive and they’re probably better armored than you are.

And of course an engagement in contact like this is unpredictable. Perhaps in some areas, your lines push forward, whereas in other places it bends back. For large maneuver units (like taxeis!) this can be a real problem, but Roman maniples are small, so one maniple can advance if it fights the opportunity while others hold position or are even forced back (we actually see a general give, essentially, an ‘advance at your own discretion’ order at Pydna, Plut. Aem. 20.8).

After a short and terrifying experience – these moments of shock combat probably didn’t last all that long, perhaps as little as just a few minutes – the hastati fall back. The front of your line is already physically and mentally exhausted. Many men are wounded and certainly some have been killed or disabled. I don’t want to oversell the casualties aspect of this: armies don’t annihilate each other in stand-up engagements (instead more casualties happen in pursuit), but wounds and exhaustion matter. Latin has this phrase, of being confectus vulneribus, “exhausted by wounds” or perhaps “worn down by wounds” (Liv. 24.26.14, 31.17.11, Caes. BGall. 5.45) to describe how the accumulation of a lot of little wounds can sap soldiers of their ability to resist effectively, even if no one wound is lethal. And just as important, all of the emotional impetus of your initial attack is spent. And there’s a decent chance that, as you try to breath, you still have these light velites javelins (the hasta velitaris) thudding into your line every few seconds, because – again – they carry seven of them. They’re not out.

And then, as you are getting your bearings, trying desperately to catch your breath, the principes come up. They’re not physically tired or emotionally exhausted, but eager (like you were a half an hour ago when you advanced), they’ve been waiting all this time. Worse yet, these are probably the most combat-effective soldiers the Romans have, in the prime of their life, with years of combat experience. Now the second volley of pila comes in, creating yet more chaos. And then more angry, heavily armored Romans, behind their big shields, stabbing and cutting with their deadly gladii.

Now the men at the back of your single line may be relatively fresh, but you have no real way to get them to the front, so the wrath of the principes falls on men who are already exhausted, already wounded, already tired and already out of fight. Your line isn’t advancing so stridently; the men in the back, if the formation is deep, don’t know why the advance is slowed, why the line seems to be wavering, only that it seems to be wavering. And meanwhile, everyone is hoping that, at any moment, the victorious cavalry on the flanks is going to show up and win the battle, but they can’t see it anywhere in the confusion. Maybe your cavalry has won and is moments away – or perhaps Antiochus III charged it off the field again and no help is coming. Or perhaps the enemy cavalry has tied it up or worse yet, the Roman’s highly skilled Numidian allies might have mastered the flanks. You have no idea, you only know that help isn’t here, you are tired and more Romans are upon you. And somewhere, the thin thread of human courage snaps, either from the exhausted men in front or the confused men behind and the formation begins to collapse.

As the collective defense of lapped shields or serried pikes gives way, the Romans are now truly in their element: their large shields function just fine in individual combat and their versatile swords do as well. Lead by their centurions, the principes, with practiced and experienced skill, are finding the gaps, cutting as they go. As the formation crumbles, the velites can pursue – lightly armored, but well enough armed, backed up by the equites if there are any left.

Attrition and Friction

You can see thus how this is a formation designed to wear down an enemy’s main battle line. It isn’t that the Romans are set massively deeper than a Hellenistic army, either. Assuming a base-3 set of file-depths (which seems to me the most likely), the Roman ranks are probably six, six and three men deep (hastati, principes, triarii), for a total depth over each file of 15, one less than the normal Macedonian formation. And with the wider fighting intervals the Romans use, they won’t normally have much of a problem matching the fighting width of the enemy army, unless substantially outnumbered (as, for instance, at Magnesia).

It’s not the Roman formation is deeper, its that its successive battle lines avoid exposing the entire army to exhaustion, attrition and friction all at once. In effect, it uses the same principles as defense-in-depth, exploiting the effect of friction on the enemy line to wear it down, but does so on the offensive. I don’t think it is an accident that when the Romans do lose, it tends to be because this model battle was spoiled in some way, either because the army was ambushed, enveloped, something disrupted the triplex acies or because the enemy was able to carry the field with just the momentum of the first charge – the Roman lines essentially failing like a building undergoing controlled demolition, as each floor pancakes the next without slowing.

But an army that isn’t able to decisively win the battle either at the first onset or somewhere else on the line is going to find itself in quite a lot of trouble as the Romans almost inevitably sandpaper away the morale and stamina of the main line of resistance until it collapses.

Now many of you may already be realizing that this kind of force is going to present a Hellenistic army with a lot of problems, both because it is set up for a different kind of fight than they are, but also because it may end up matching much heavier troops against the lighter parts of a Hellenistic army. But before we jump into battles, we need to zoom up to the upper levels of military analysis – operations and strategy – and talk about the advantages the Romans have there.

Because if all the Romans had was an edge in their tactical system, we might expect them to win battles but sometimes lose wars. Instead, while the Romans sometimes lose battles, they seemingly always win the war. And that’s where we’ll look next week.

1. This gag amuses me more than it should.
2. On this, see Burns, M. T. “The Homogenisation of Military Equipment under the Roman Republic.”  In Romanization?  Digressus Supplement I.  London: Institute of Archaeology, University College London, 2003.
3. On this, M.J. Taylor, “Roman Infantry Tactics in the Mid-Republic: A Reassment” Historia 63.3 (2014): 301-322.
4. To expound at some length on my own thoughts on how I think the wealth/age issue was probably managed, Dionysius (4.19.2) claims that the Romans recruited by centuries in the comitia centuriata such that the wealthy, divided into fewer voting blocks, served more often, and we know from Polybius that the maximum period of service for the infantry was sixteen years and from some math done by N. Rosenstein in Rome at War (2004) that the average service must have been around seven years. My suspicion, which I cannot prove is that the very poorest Roman assidui (men liable for conscription) might have only been serving fewer years on average and so it wasn’t a problem having them do all of their service as velites (the only role they can afford), whereas wealthier Romans (my guess is pedites IV and up) are the ones who age into the heavy infantry, with pedites I, whose members probably serve more than the seven-year average (perhaps around 10?) might make up close to 40% of the actual heavy infantry body (which is their balance in the comitia centuriata). The velites thus serves two important functions: a place to ‘blood’ wealthier young Roman men to prepare them to stand firm in the heavy infantry line, as well as a place for poorer Romans to contribute militarily in a way they could afford. But I think that, once in the heavy infantry, the division between hastati, principes and triarii was – as Polybius says (6.21.7-9 and 6.23.1) – an age division, not a wealth division Instead, the next wealth line is for the equites.
5. The data on this is compiled by Taylor, Soldiers & Silver (2020), 26-28.
6. Taylor, op. cit., 54-7 compiles examples.
7. We discussed this problem in the scholarship here.
8. For more examples, see Zhmodikov, “Roman Republican Heavy Infantrymen in Battle (IV-II centuries BC)” Historia 49.1 (2000), fn. 31.
9. Important word! Our sources, as we’ll see, for the Pyrrhic War, aren’t very good and some of those battles are beyond confident reconstruction.