Ancient army numbers

[Nathan Ross]

How large were the largest Roman expeditionary armies?

Roman army numbers are also, I believe, commonly inflated. I've argued here, for example, that the figures of hundreds of thousands of men suggested for Trajan's Dacian campaigns are probably mistaken - the actual total for the force was more likely 50-60,000.

Lee (War in Late Antiquity) notes that 4th century campaign armies were comparatively small; 15-30,000 is typical. One of the largest appears to be Julian's Persian invasion force, of around 65,000 men. Trajan's Parthian expedition probably had very similar numbers.

A few Roman-related figures on the supply problem:

Goldsworthy (Roman Army at War) estimates that a single legion of c.5500 men would consume 100 bushels of corn a day: the equivilant of 70 acres agricultural production a week*. A legion also ate 12 oxen, 120 sheep or 38 pigs per day, and required nearly 1000 baggage mules (who also needed fodder, of course)

* I think he gets this figure from Piggot, Roman and Native in North Britain; but Piggot gives the figure as 20 acres!

Lee (again, as above) estimates that an army of 10,000 men required 23.5 tons of food per day, including fodder for 4000 cavalry with 1000 remounts. hock:

Muliplying these rough figures gives some idea of the astronomical demands that a large army would place on food production and supply. Keeping tens of thousands of men in a cohesive group in the field would strip whole areas - an army of 100,000 or more would leave entire provinces denuded of food, with famine in its wake; the logistical problems of collecting the food and delivering it as a daily ration would be immense, and half the army would probably be starving before they even reached the battlefield!

Going back to the Greek v Persian issue - might it be possible that the irrigated farmlands of, say, Mesopotamia would have been far better for supporting large armies than the less cultivated lands of Greece? The Persians may have been able to field an army hundreds of thousands strong on their own territory, but would they take such a force on expedition into country less capable of supporting them?

:-?

[Darth_Roach]

Going back to the Greek v Persian issue - might it be possible that the irrigated farmlands of, say, Mesopotamia would have been far better for supporting large armies than the less cultivated lands of Greece? The Persians may have been able to field an army hundreds of thousands strong on their own territory, but would they take such a force on expedition into country less capable of supporting them?

:-?

I was going to say "nice post" but then I saw this one last part, a typical attempt to twist numbers even in the face of logic. How exactly would the Persians be able to out-supply Rome, considering legionaries did away with the otherwise ubiquitous camp trail? Not to mention the fact they had to be supplied thousand of kilometers from Mesopotamia. Even in Mesopotamia itself, an army of 100 thousand would be absolutely ruinous to economy.

[Nathan Ross]

How exactly would the Persians be able to out-supply Rome... Even in Mesopotamia itself, an army of 100 thousand would be absolutely ruinous to economy.

I was referring back to the initial suggested estimates of Xerxes' army in his invasion of Greece. My point was that within the boundaries of the Persian empire, Xerxes' total army strength could have numbered in the hundreds of thousands, as agricultural production in some areas of the empire may have been sufficient to support comparatively large numbers (although not all in one place!), but that he would be unlikely to lead an army of that size on campaign into an area less well cultivated and therefore unable to supply such a force. So I was actually agreeing with you, I think :-?

[Darth_Roach]

Again, what makes you think they could field more than the Romans could?

[Nathan Ross]

Again, what makes you think they could field more than the Romans could?

Ah, Ok, I see your point. I was talking about total army size, so my use of 'field' in the above post was probably ill-judged. The Roman army surely did number in the hundreds of thousands (389,704 under Diocletian, if we believe John Lydus), and possibly the Persian army, with a vast empire to draw on, did likewise. So to say (for example) that Xerxes had an army of hundreds of thousands of men may not be wrong, but to assume that he brought this number with him on his invasion of Greece would defy probability.

[Gaius Julius Caesar]

I wonder.
The Persian empire was vast, had excellent roads, an efficient communication system, well organised goverment of it's provinces. It could draw on manpower from the heart of civilisation, and was able to cross the Hellespont on a pontoon bridge.
But it couldn't organise, mobilise, equip and supply a vast Army?
They dug a canal across the Halkidikki peneinsular to avoid a storm...
Surely, they were an advanced society, and were capable of planning a campaign which relied on both supplies, and requisitioned supply from the lands it crossed?
The Balkans were surely not totally un-cultivated and barren.?
Anatolia was considered a ripe fruit by the Greeks...full of untold bounty.
i think the vastness of the account of the Greeks to describe this would have been inclusive of the vast supply train.

[D B Campbell]

You can't really compare the 19th c. to the 5thc. BC I think.

Well...not sure I agree with that entirely.

I'm with you, Moi. Pre-modern, pre-industrial scenarios (especially where they are well-documented) can often give us a striking insight into the ancient equivalent. (Off the top of my head, I can think of one study which compared Boer War/Zulu War logistics with Roman logistics.)

[Vindex]

why thank you!

I would be tempted to say anything pre-manoeuvre warfare strategy can provide some interesting comparisons, although I don;t know about the Boer/Zulu war one. One assumes it is before the concept of hub and spoke supply...

[sonic]

Just to put the cat back amongst the pigeons .... :-D

When Julian led his (65,000 according to Nathan) men to attack Persia, they stopped at Antioch. There was then a problem when a local drought and the presence of the army caused food shortages. Julian had to spend freely to import extra supplies of food for the city and the army (Jul. Misopogon 369a-b).

When combined with the population of the city, the numbers would equal those claimed by the sources for the extremely large armies. This implies that supplying such numbers far from home would be very difficult, if not impossible.

Any thoughts?

[Ghostmojo]

OK. I'm not sure why we have two threads on this? Perhaps this one could be renamed Thermopylai Logistics (rather than about a film as such)?

But in any event, I am also dubious about the provisioning of such a huge force. I can't remember if it was Leonidas or not, but one Spartan said "the Persians come to rob us of our poverty"!

Xerxes would perhaps have left a sizable chunk of his army in the better provided Thessalian plains, because I think the Malian terrain was probably less bountiful, to put it mildly. Once the plug at Thermopylai had been removed the remainder could have followed his advance contingent. Even so one has to wonder about the water issue in a country like Greece so notoriously dry - and in August too.

PS. I note the thread has actually been renamed now ... :oops:

[Darth_Roach]

Doesn't really matter where he'd winter his troops, since 100 thousand is too many to field in the first place.

To throw about some arbitrary figures, I'd say some 80 thousand (where does the 79k estimate come from - not sure) troops originally and then 40 - 45 thousand wintering troops.

[Sean Manning]

I wonder.
The Persian empire was vast, had excellent roads, an efficient communication system, well organised goverment of it's provinces. It could draw on manpower from the heart of civilisation, and was able to cross the Hellespont on a pontoon bridge.
But it couldn't organise, mobilise, equip and supply a vast Army?

By any standard before the intersection of booming population, fossil fueled industry, and conscription in the late 19th century, tens of thousands of warriors in one place was a vast army. Six hundred triremes, or 120,000 men, certainly is a vast force! All we can really say about the Persian invasion force was that it had tens of thousands of soldiers (the majority Median, Persian, Bactrian, and Saca infantry with some Greeks and Indians and cavalry), hundreds of triremes, and scared the chitons off the Yauna-beyond-the-sea.

Roach, the few ancient references that I have seen suggest that the Greeks and Romans considered one noncombatant per soldier an unusually high ratio. Defining "noncombatant" is always complicated; Xenophon wasn't on Cyrus' muster roll, but he brought arms and horses and tried to make himself useful.

[Sean Manning]

You can't really compare the 19th c. to the 5thc. BC I think.

Well...not sure I agree with that entirely.

I'm with you, Moi. Pre-modern, pre-industrial scenarios (especially where they are well-documented) can often give us a striking insight into the ancient equivalent. (Off the top of my head, I can think of one study which compared Boer War/Zulu War logistics with Roman logistics.)

They are also informative about the difficulties of such estimates even in well documented periods. I hope to be able to discuss briefly in my MA thesis on Achaemenid logistics the problem of Agincourt: Anne Curry has records for numbers on both sides in terms of men at arms and archers, but she makes two debatable assumptions- that English records accurately reflect the number who died of disease at Harfleur, and that the French gros valets or coustiliers (servants with arms, harness, and a horse) don't count as combatants. In England a gendarm's male servant usually fought as an archer and was enrolled among the archers so his master wouldn't have to pay his wage. She also has documents that show that there was a trickle of reinforcements during and after the siege as individual lords sent word to England and enrolled substitutes for the sick and the dead.

[Paralus]

Yes, they planned to stick around (as in fact they did), living off the land. And seeing the Persians did not starve, they were probably able to gather suppies within Greece, something I doubt they could have done with an army of 300.000. But that's my guesswork.

Herodotus' numbers are vastly inflated. At 9.15 Herodotus says that Mardonius built a walled encampment some ten stades square. Wherefore to fit 300,000 plus cavalry mounts and everything else to go with the army? There is also no indication that, at Plataea, the Greeks were outflanked by massive Persian numbers. The Greek force was some 38,000 plus hoplites. Herodotus gives no role whatsoever to light Greek troops in the battle (which is not to say there were none though I doubt 35,000 helots to 5,000 Spartans) and it is unlikely that psiloi will have been used as infantry of the line. We are, then, forced to assume that Mardonius deployed his infantry something between 40-50 deep?

It is near certain that Mardonius had supply problems. Thucydides (6.33.5-6) puts the following words into the speech of Hermocrates as the Athenians sail against Syracuse:

Few indeed have been the large armaments, either Hellenic or barbarian, that have gone far from home and been successful. They cannot be more numerous than the people of the country and their neighbours, all of whom fear leagues together; and if they miscarry for want of supplies in a foreign land, to those against whom their plans were laid none the less they leave renown, although they may themselves have been the main cause of their own discomfort. Thus these very Athenians rose by the defeat of the Mede, in a great measure due to accidental causes...

The Greeks will have, eventually, fallen foul of each other had Mardonius waited. He did not wait though; rather he continued to seek a showdown and this is likely for reasons of failing supply once the fleet had departed.

Herodotus, himself, even seems embarrassed by some of his figures. Having told us that Xerxes sailed with 1,207 ships he realises that the 330 odd ships of the Greek fleet at Artemesium are plainly not in the fight. He thus prepares the way for the battle of Artemesium with a couple of timely correctives. Firstly he removes 200 Persian ships by sending them to destruction circumnavigating Euboeoa. Still with much leveling work to do, enter "storm soter" (Her.7.190-191)...

They say that at the very least no fewer than 400 ships were destroyed in this labor, along with innumerable men and abundant wealth [...] There was no counting how many grain-ships and other vessels were destroyed. The generals of the fleet were afraid that the Thessalians might attack them now that they had been defeated, so they built a high palisade out of the wreckage.

So the loss of 600 fighting ships brings the Greeks back into the realms of possibility!

Going back to the Greek v Persian issue - might it be possible that the irrigated farmlands of, say, Mesopotamia would have been far better for supporting large armies than the less cultivated lands of Greece? The Persians may have been able to field an army hundreds of thousands strong on their own territory, but would they take such a force on expedition into country less capable of supporting them? :-?

Command and control are still the problem. The Helleno-centric sources are very fond of the monstrous hordes that make up Persian armies. Xenophon, without the merest reflective thought, would have it that Artaxerxes had 900,000 at Cunaxa and should have had 1,200,000!

The Greek sources claim that Darius III marched 600,000 (plus supply animals) through the Bache Pass to Issus. Reduced to (a generous) four abreast and a metre of spacing through the mountains, this army will have stretched 150 kilometres (not counting supply animals. And this will have been similar wherever supply wagons and such demanded roads to move on.

[Sean Manning]

The Greek sources claim that Darius III marched 600,000 (plus supply animals) through the Bache Pass to Issus. Reduced to (a generous) four abreast and a metre of spacing through the mountains, this army will have stretched 150 kilometres (not counting supply animals. And this will have been similar wherever supply wagons and such demanded roads to move on.

Indeed. We very rarely see anything like the Napoleonic practice of dividing armies into corps which marched separately but came together briefly to fight, in the ancient world. This is what briefly made it practical to gather a hundred thousand or more men in one place, until population growth and high explosives forced armies to spread out again in the 20th century. Herodotus says that Xerxes' armament gathered in Cappadocia and wintered inland at Sardis, so clearly it could survive for months without waterborn supply or splitting up.