I have counted legions and allied legions Rome conscripted during 16 years of Punic War. It's roughly 400k and could be even more.

Battle Year Result
Battle of Ticinus 218 BC 2,000 Roman casualties, Carthaginian victory
Battle of the Trebia 218 BC 25,000 Roman casualties, Carthaginian victory
Battle of Lake Trasimene 217 BC 20,000 Roman casualties, Carthaginian victory
Battle of Ager Falernus 217 BC 1,000 Roman casualties, Carthaginian victory
Battle of Geronium 217 BC 10,000+ Roman casualties, Carthaginian victory
Battle of Cannae 216 BC 70,000+ Roman casualties, Carthaginian victory
Battle of Capua 212 BC 1,500 Roman casualties, Carthaginian victory
Battle of the Silarus 212 BC 15,000 Roman casualties, Carthaginian victory
Battle of Herdonia 212 BC 15,000 Roman casualties, Carthaginian victory
Second Battle of Herdonia 210 BC 15,000 Roman casualties, Carthaginian victory
Battle of Canusium 210 BC 20,000 Roman casualties, Carthaginian victory
Battle of Petelia 209 BC 2,000 Roman casualties, Carthaginian victory

Total losses just from this table alone are staggering 200k. (it comes close to 300k if stelemate battles are counted) What the hell?

In 215 BC the Romans had 12 legions and auxiliaries left, approximately 108,000 men of a total force of 260,300 men in 218 BC.

By early 215 BC Romans were fielding at least 12 legions; by 214 BC 18; and by 213 BC 22. By 212 BC the full complement of the legions deployed would have been in excess of 100,000 men, plus, as always, a similar number of allied troops. The majority were deployed in southern Italy in field armies of approximately 20,000 men each. This was insufficient to challenge Hannibal's army in open battle, but sufficient to force him to concentrate his forces and to hamper his movements. Goldsworthy, Adrian (2006)

In 211 BC the Romans had 25 legions and auxiliaries, 7 legions more than in 214 BC, approximately 225,000 men all together, Hannibal managed to kill or capture 45,500 men during the same time it took the Romans to raise 13 legions, or 117,000 men, so they were one step ahead of him.

Since casulties are about 200k-300k, how in the world can a pre-industrial nation that doesn't even have control over entire Italy produce that much equipment, and even equip heavy infantry, while Carthage, much wealthier nation didn't have that much heavy infantry? Or Persians under Achaemenid rule didn't conscript that many despite being far, far more richer and populous?

Weren't Romans responsible for their own equipment in early Republican era? Were Romans so rich or what?

  • 14
    B. Deveraux/ACOUP has a book coming out on this topic, and has posted some of the research/conclusions. Might be useful for you. I don't have time/resources to produce a good answer, so I'll offer my hypothesis that Rome's culture was more militaristic than Carthage, and Carthage was more commercial. Carthage relied on mercenaries, Rome developed soldiers and a military machine.
    – MCW
    Commented Apr 16 at 10:55
  • 7
    “Pre-industrial” does not mean what you think it means.
    – Jon Custer
    Commented Apr 16 at 13:02
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    Two other observations that may be worth exploring. First, Rome always drew upon allies - at least half of Rome's military complex was Roman allies. Second, it is always easier to recruit soldiers when then enemy is roaming through your territory, foraging. Hannibal was a threat, and Roman/allied citizens were happy to join to repel that threat.
    – MCW
    Commented Apr 16 at 13:14
  • 1
    You do not explain how exactly you counted and I suppose that your estimate is not correct.
    – Alex
    Commented Apr 16 at 13:27
  • 3
    The Wikipedia article on ancient warfare leads me to suspect that the Romans weren't quite as special as the question seems to assume, and that other empires with similar technology had armies as large or larger.
    – Brian Z
    Commented Apr 16 at 18:43

2 Answers 2


MCW already mentioned Bret Deveraux; I will be drawing on his blog for the answer to your central question: how did Rome put so many men under arms? Regardless of the precise math, Deveraux agrees with you: Rome's armies were more heavily equipped than their contemporaries, and they were able to recover from decisive defeats by simply mobilizing more men.

But how did that happen?

Since you bring up Persians, let's first take a look at what a typical empire's army looks like. We'll use the Hellenistic Greeks for this one - but all empires essentially function the same way (a core nation that conquers, but does not assimilate, subject peoples).

At a glance (aside from the sarisa) contemporary Greeks and Romans (and Persians) have the same kind of units: heavy infantry that fight in close order, light infantry for skirmishing and harassing the enemy's heavy infantry, cavalry to go fast, and the odd elephant. But while Rome's army is composed of Romans (more about that in a bit) an empire's army is composed of subjects. The heavy infantry core can only be composed of the ethnic elite (the Macedonians, the Persians, whatever), who are more motivated and wealthier besides. The subject peoples are relegated to medium and light troops for political reasons.

And if that was the whole story, Rome might not have a fighting chance. But it's not. There's a second reason these empires tend to have trouble when it comes to mobilizing manpower:

the Seleucids needed their army for more than just war: they needed it to enforce taxation and tribute on their own recalcitrant subjects. As a result, no Seleucid king could afford to ‘go for broke’ the way the Roman Republic could, nor could the Seleucids ever fully mobilize the massive population of their realm. The very nature of the Hellenistic kingdom’s ethnic hierarchy made fully tapping the potential resources of the kingdom impossible.

Carthage had the same problem - a small core ethnic population and an army made up of vassal peoples pressed into service. And they could not afford to field and risk losing a large amount of the core Carthaginian manpower.

Sure, Rome had subject people too - but they treated them as allies, even if the alliance was unequal. As a result, with socii able to benefit from the spoils of war and even become Romans themselves, they were much more motivated to show up with their best foot forward.

As for the Romans themselves, Deveraux goes into great detail about how they raise their legions. And indeed, we find that the burden of arming each soldier falls on the soldier himself - older, wealthier men were expected to not only serve as heavier infantry, but serve longer whereas poor men could discharge their obligation with one tour of duty as velites. This innovative mechanism, combined with the motivation of everyone fighting for one's country, resulted in a much larger proportion of the population that could be put under arms as heavy infantry.

between 214 and 212 the Romans called up something on the order of a quarter of a million men (including the socii). Counting the casualties in the bitter losses of 218-216, the total almost certainly rises over 300,000, close to half of all of the military aged males liable for service in Italy...

...Unlike more bureaucratically sophisticated states which extracted vast tax revenues and then used the money to entice soldiers, Rome’s ‘serve for the honor and glory of it’ military system didn’t bankrupt the very modest resources of the Roman state.

  • 3
    I had an answer in mind myself (and may still submit it when I get home where my reference material is), but this added several (well-supported!) points I'd never thought of. +1 from me.
    – T.E.D.
    Commented Apr 16 at 14:50
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    This is a damn great answer. Shame that many youtube channels and articles don't emphasize on this most important aspect of war. Some don't even mention this at all and simply brush it over as "Romans are tenacious while Carthaginians are coward and effeminate and loved commerce and money" as if that makes any sense. I have always thought Carthaginian overall population was very small since almost all of their cities were colonies dependent on other cities. Then, considering North Africa was breadbasket of Meditteranean, this assumption is clearly wrong.
    – ÖzgürP
    Commented Apr 16 at 15:56
  • 21
    "The manly Roman Empire" is sadly a very common trope, and goes hand-in-hand with another one that Deveraux debunks - that Rome fell due to becoming "too diverse." In actual fact, Rome's ability to absorb conquered peoples made it rich and stable, while the barrier erected between Romans and allies under the foederati system was a significant factor responsible for its collapse in the West.
    – SPavel
    Commented Apr 16 at 16:58
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    Deveraux's blog is very in-depth and yet insanely easy to digest. Fun even.
    – Yorik
    Commented Apr 16 at 17:02
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    @RobertF the various Italic states were mostly related peoples to the Romans with similar languages, so integrating them as subordinate allies wasn't too difficult. It's as if Sweden had conquered and subordinated Denmark, yeah, there would be unhappiness, but nothing too drastic. Whereas Semitic Carthaginians, who weren't originally even from the same end of the Mediterranean could not hope to do that with the Iberic/Berber peoples, hence the imperial form of government. When Rome began conquering more and more foreign peoples, they had to change to the imperial form too.
    – Eugene
    Commented Apr 17 at 20:18

It's worth adding that unlike in modern societies, Rome relied on slave labor to a good extent. These don't count as citizens who could join the army, but they do substitute them on the labor/home 'front', meaning a larger proportion of citizens could thus be soldiers.

How many slaves exactly were in the Roman empire at any given time is however difficult to estimate. Still some attempts were made, e.g.:

From evidence such as this Westermann, Hopkins and others are understandably cautious when attempting to come to a total figure for slaves in the city of Rome in the 1st century AD. Hopkins' estimate of 300,000-350,000 out of a population of about 900,000.

Other estimates on the number of slaves (p. 132) are in the range of 200,000 to half a million, even in the period 225-168 BC. [Also, the number of adult male citizens (in the empire) had risen to 1.4 million by the Augustan period. (But see below for more on that.)] One tally of the slaves captured between 217 and 167 BC is 388,000 (p. 136) but this probably doesn't include those traded/bought.

Generally speaking, the demographics of the Roman empire are still subject to [much] debate; quoting a [2013] book review (doi:10.1017/S0075435814000380):

From the early debates between David Hume and Robert Wallace, efforts at macro-scale reconstruction of the Roman population have been marked by the wildest divergences. Fundamental disagreements still abide between ‘high-counters’ and ‘low-counters’, who offer not just different interpretations of Republican and Augustan census figure but entirely irreconcilable visions of the trajectory, scale and nature of Roman development. Saskia Hin’s Demography of Roman Italy is a remarkable contribution in many ways, but above all in that it is the only compelling attempt, in over two centuries of research, to offer a comprehensive middle way. Indeed, she provides the reader with a memorable handle for her reconstruction: the middle count. [...]

In the final section, H. takes the insights earned in the previous chapters to reconsider the problem of total population size. She offers a novel solution to the classic problem of the relationship between the census figures reported by Livy for the late Republic and the Augustan figure. To oversimplify the issue, low counters argue that the earlier figures included all adult male citizens and the Augustan figures included all citizens, for a total population under Augustus of around four million. High counters argue that the Augustan figure included only adult male citizens, so that the total population was maybe three times larger, or twelve million. H.’s ingenious argument is that the early figures report sui iuris adult male citizens, while the Augustan figure included all citizens, including women and children, sui iuris. Her principal evidentiary support for this view (though she marshals a range of circumstantial evidence) is Livy’s remark that the earlier census did not include widows and orphans; this statement, she argues, suggests a change in which subsequently widows and orphans sui iuris were counted. A weakness of this argument, already pointed out by de Ligt, ‘is that married women sui iuris, one of the groups supposedly covered by the Augustan figure, were evidently neither pupillae nor orbae’ (Peasants, Citizens, and Soldiers, 127). Thus, though H.’s reconstruction is satisfyingly harmonious with a model of moderate long-range population growth in the late Republic, it will not be the last word. Her final chapter, engaging with Launaro’s reconstruction from survey archaeology, convincingly makes a case for more limited growth between the late Republic and early Empire. Ultimately, the overall shape of the middle count model, with moderate population expansion in Italy continuing into the first century C.E., is in broad terms attractive, though the details of the census figure remain stubbornly confounding.

So, as a kind of conclusion on this angle: whether the army was large or small relative to the [whole] population depends how big the (ahem) population was. Which for the Romans we only have some disputed/interpetable numbers... some centuries later.

If you're willing to entertain undercounting (of the poorer population), then specific theories have been advanced, e.g.

How was Rome willing and able to maintain such enormous military forces, even as its traditional manpower pool shrank? The answer is surprisingly obvious, even if our sources do not fully admit it. During and after the Second Punic War, the Romans must have disregarded the wealth qualifications for military service. The proletarii, the Romans too poor to afford citizenship, were a large group which the census routinely undercounted. It is only through their widespread participation in the military that we can explain Rome’s ability to wage war on such a scale and for so long.

Indeed, the census bears out this theory. In 193, just five years after listing 144,000 Romans, the population of Roman citizens leapt up to 258,000. The only explanation for such a rapid rise is a change in the way Rome counted citizens. It seems likely that Rome became more willing to give out citizenship, partly as a way to bolster its manpower, and also that Rome began to devote more effort to counting the proletarii, whose military service was finally vital to the state.

The sources do not mention the widespread recruitment of the poorer classes, but Polybius does suggest that the Romans did sometimes ignore property requirements. The Roman historian Livy, for his part, recounts the story of Spurius Ligustinus, a poor Roman who joined the legions in 200 BCE and served for 22 years, winning immense fame for his courage and skill. Livy mentions that Spurius Ligustinus did not meet the minimum criteria to enter into the legions, yet he gained entry nonetheless, despite the fact that the Second Punic War was by that point won. The existence of soldiers like Spurius Ligustinus points to a systematic bending of the property qualifications in the Roman army, even after the crisis of the Second Punic War was over.

Note however that Wikipedia somewhat disagrees with this:

For much of the 20th century, historians held that the property qualification separating the five classes and the capite censi was reduced over the course of the second century to a nugatory level due to a shortage of manpower. The basis for that belief, however, was merely three undated Roman figures for the amount of property required to serve which would serve as evidence for reductions only if forced into a descending order.[18][19] Many scholars have also now abandoned the notion that Italy suffered in the second century BC any deficit of manpower which would have driven such putative reductions.[20][21][22]

Whether that's a fair summary of the scholarship, I'm not sure. The sources 20-22 are a book in French (PhD thesis) and this 1983 45-page paper.

OP quotes

In 211 BC the Romans had 25 legions and auxiliaries

These numbers have also been somewhat disputed in that last paper I mentioned (and which Wikipedia considers authoritative), but anyhow that peak figure seems to diverge from the mean in later years a fair bit:

If Livy's legion lists are authentic, 20 or more legions were in service every year from 214 to 206, with a peak of perhaps 25 in 212. Although I am sceptical about a good deal of Livy's information on this subject, I think it unlikely that the totals he implies should be much reduced. Calculations of the number of men serving can only be conjectural, for many of the legions must have been seriously under strength. Brunt estimates that there were never less than 60,000 legionaries in service between 215 and 207, with a peak of 80,000 in 212. These figures are likely to be of roughly the right order of magnitude, and may even err on the side of caution.

The number of legions and legionaries in service in the years 200-168 have been calculated by Afzelius and Brunt on the basis of Livy's evidence. Although some points of doubt subsist, the margin of error is not likely to be great. On Brunt's figures the average number of legions in the field in these years was 8.7. If we assume that the legions were kept up to a nominal strength of 5,500, the average number of legionaries was 47,850. In thirteen years ten or more legions were in service. During the war with Antiochus Rome fielded 12-13 legions: her effort then was of the same scale as in the Hannibalic War.

[...] It is unlikely that as many as ten legions were fielded except for two brief periods, 148-6 and 105-1, and possibly the year 135. The average number of legions in the intervening period according to Brunt's table is 6.4 - at full strength, 35,200 men.

Whether that's because the greatest emergency/motivator had passed or the numbers were a bit inflated for 211, YMMV. Anyhow, the number is service at any given time is well below the cumulative dead.

  • 2
    If that was the case, Carthage should have the larger army, since it is known that Carthage was a prime slave trade hub and was absurdly rich.
    – ÖzgürP
    Commented Apr 17 at 16:54
  • @özgürpeynirci: depends whom exactly they could include in their army. The slaves probably not. Anyhow, if you also want to ask about population estimates for Carthage (incl. their slave pop.) you should ask that separately. Commented Apr 17 at 17:25
  • 1
    Rome had a smaller slaves-to-citizens ratio than, for example, the Greeks.
    – SPavel
    Commented Apr 17 at 18:22
  • @SPavel: could well be, but it's not that relevant here. (I made comparison with modern societies, not with the ancient Greeks) If the Romans had ~400K slaves... Commented Apr 17 at 18:23
  • @özgürpeynirci: alas we know very little how many slaves Carthage had. The only concrete figures that made it to us were apparently that they managed to buy 5,000 in one year, to row their ships, which indeed was deemed a great feat for Greek cities generally could not afford something of that magnitude (in that short of a time span). Another figure is that one of the factions in one of their civil wars used/impressed 20,000 slaves as soldiers. But that faction lost the war. So the quality of slaves as soldiers... somewhat debatable. Commented Apr 18 at 1:47

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