Ancient army numbers

[Macedon]

Well, some may do this with a light heart, I’m not one of them. On the other hand, numbers are to be treated with extreme caution when dealing with sources in general, as we have to with Ancient sources. The biblical number of Israel being able to field a million men-at-arms are no different than the million men invading Greece.

I agree. I myself am critical of Herodot's numbers but I also am critical of superficial "studies" that easily dismiss "huge" armies because in the opinion of their authors, the ancients just did not have the manpower or the technology to support them. I generally find that there is a great issue regarding actual capabilities of the eras in question. Of course some accounts are less plausible than others, some being openly mythical, I just point out that we have to be more careful when we are talking about the capabilities of the ancients. As you may have read, although I do believe that the Achaemenid Empire COULD have organized even a campaign as great as Herodot's assertions, I would find such numbers improbable because they would just be useless in the operations, draining resources without offering anything in the process.

Regarding the invasion of Greece by Xerxes army, I have no doubt that this army was large, that much is clear from the sources. Whether we are to trust the estimates presented to us by the sources is quite another matter. Overestimating an army is quite a normal practice, and I generally mistrust round numbers such as ‘100.000’, but that’s me.

Of course. The thing is what would "large" mean for a campaign such as that and what parts of that force should we include in these numbers.

But even if we disregard the level of ancient source trustworthiness, we can ask questions about more practical matters.

The ancients also made that discussion. Diodorus, Polybius... they did address the issue of trustworthiness, especially when it concerns large armies. Of course there is an issue that can never be fully resolved. To get nearer to the probable truth, though, we should establish some rules that show us the capabilities of armies in the eras in question first. This does not of course mean, that because the capability might exist, it would also be stretched to its upper limits. Many more factors would ordain strategical decisions apart from initial availability of supplies.

Your first question rightly regards logistics. However, you don’t seem to question the amount of supplies. Why not? The Persian empire, though vast, was not a vast exporter of food. It controlled Egypt and Asia Minor of course, but we can hardly expect the local populations to have starved while their food was being transported to the Greek War effort.

I thought I was clear on that. My opinion was that these men, whether 100,000 or 100,000,000 would anyways consume supplies at home. The problem was not the availability of supplies but the capability of transporting the supplies to the troops. There was no need to have the population starve. Xerxes had 3 years to organize the collection of supplies and this time was more than enough to make the provisions amassed in the supply centers necessary for the campaign. So, it was a matter of organizing the existent resources rather than having to produce more of them.

But even leaving that question aside, did the Persian state indeed have the logistical capabilities to feed such a vast host? I’m no expert, but I have not yet come across any evidence that tells us that they did. I’d love to be proven wrong though.

This is the key question of course. To this I maintain that the use of ships was crucial. What kind of evidence would you like to come across? Simple math can back this assumption up if we take for granted that enough cargo ships were available and adequate organization in matters of the science of logistical support, which I would not personally doubt. As I support, campaigning away from the sea is very different to campaigning near it AND at the same time enjoying sea lane control.

As evidence, I would urge us to look up the attested amount of grain that was daily imported to Athens via the sea lanes. I do not at the moment remember the sources but it was a considerable amount of shipments every day, clearly showing that this was no territory of the unknown. Herodot also writes of merchant fleets sailing to Athens with provisions. So, if such supply fleets already operated in the Aegean - and feeding the Athenian population was no simple task, since Attica itself was not sufficient - and the rest of the Mediterranean, I can see it as self-evident that such a mechanism would have easily worked to support the Persian army as it marched along the Greek coastline.

Again, being able to support a huge army does not make it necessary for the army to have been huge, just possible. Had it been a landlocked campaign, the capabilities would have been vastly inferior.

Next question, army numbers. From your post I seem to understand that you consider the Greek forces to have been a certain number and from that that a vastly superior number of Persians was needed, making a very large force acceptable?
Where did this large Persian army come from? Even when we look at far better documented campaigns (Xenephon, Alexander) we never hear of armies even a fraction of the numbers (5 million!!) that you seem to find acceptable. Even the largest numbers given to the entire Roman army (Agathius, more than 600.000) is dwarfed by that number. I really don’t understand where you find such a number, apart from perhaps taking some percentage of an estimated total of the Persian population?

Right. First, I wrote that I do consider Herodot's numbers inflated. I do not agree with his numbers, yet NOT on reasons of capability but of strategical necessity. Secondly, I raised the question of what his numbers depicted. Herodot calculates a total of 5 mil but half of them are camp followers. Camp followers were not normally supplied by the army and certainly not if there was any want of supply. Thus, 2.5 mil of this total, even if indeed following the army, although it could be a rule of the thumb for Herodot who does not further analyze their numbers of course, would actually only follow the army for as long as their own supplies were adequate. Some would have been better organized, some would have connections and knowledge of how to procure more supplies but most would not. So, most of this huge train would have been back in Asia before Xerxes marched south of Macedonia. Herodot does never again talk of this throng of followers and this could be a reason why. So, subtracting that, we would have been left with 2.5 mil, vast indeed, but half of the initial number. Even that number I, as already stated, find too much. Yet, a mil (in ALL branches), I would personally not find too much. What is important in the figures I hold as probable is the fact that I keep Herodot's account of the Persian navy and make all reductions in the numbers of the land army. So, I believe the 250-300,000 men employed in the navy are very plausible AND probable and personally would suggest a Persian land force of 700,000 men (which is less than 1/3 the account of Herodot). So, in my opinion, the Persians would have been half as many but their land force 1/3 that. I indeed accepted that mustering such a number (2.5 mil)would indeed have been possible, but again, being possible does not mean that it happened. I just wanted to refute the "they couldn't" argument. The US being able to field today millions upon millions of troops does not mean that this is what they would send to Iraq, my point being that it is other reasons we should be looking for rather than availability of manpower. And yes, strategically, if the Greeks were expected to be able to field great numbers, Xerxes would also be expected to invade with a force superior in numbers by far. The strategical reasons for that would, to me, be more interesting to discuss, so that we might find out what numbers would have made this campaign probable to succeed.

The same goes for the Greek forces for that mater: a 100.000 at Plataea as a fraction of the Greek forces – are there sources available that ever mention all Greek armies, added together, as 500.000? If they had been able to muster such forces, the Romans would never have managed to gain a foothold! Or had the Greek population shrunk that much by the time of the Roman invasion? Or are you counting every man, woman and child involved in keeping the warrior in the field? I believe the ratio is 5 to 1, so for every soldier you’d need 5 non-combatants? That would explain large armies but not large fighting forces.

No, we have to make additions. At the time of Plataea, there would be a large army operating against Mardonius, another one in Ionia, the crews of the Greek fleet, the armies of the Greek states that were not taking part in the campaign, those that would stay as garrisons and reserves and of course those that belonged to the medized Greeks which would as easily turn against the Mede if he was unquestionably beaten. To these, one could also add the (or a part of the) Greeks of Magna Graecia and Sicily, who at the time fought against a similar threat, a huge invasion of Carthaginians in Sicily. If you only add up these numbers you will find a total of "Greek" ACTIVE army attested (in very plausible numbers) actually larger than my proposed 300-400 thousand. In Greece proper alone, more than 200,000 would be actively employed against the Persians, no garrisons, reserves or levies counted, if we only accept the 100,000 men at Plataea as possible (to me this is a very possible number and was not viewed by the Greeks as very high or improbable).

As for the Romans, had the Greeks united, they would indeed never have gotten a foothold. They warred with Greek allies against fragmented Greeks. And of course, just because one can muster great armies, that doesn't mean that this will indeed happen. You need men back home, both as standing army and as financially active members of society. In these number I do not count camp followers who would not be many in domestic campaigns or in those where the hope of booty would be limited. I consider the total Greek population of the Mediterranean as quite larger than that of the rest of Italy. The issue is that they were very fragmented and usually (and correctly so) viewed as individual separate entities (Greece proper, Northern Greece, Islanders, Ionia, Cyprus, Magna Graecia, Sicily, Western colonies, Black sea Greeks, Cyrenean Greeks). Every one of these groups was very sizable, some more, some less. I think that 300-400,000 could and maybe did operate against the Persians in all theaters (a part offensively, another defensively as garrisons).

Also, the matter of logistics is to be considered. Greek forces, being close to home and able to be supplied locally, would logically represent a much higher percentage of the population than an invasion force far away from home.
Considering the Persian fleet, I can understand how their crews would inflate the numbers of the army, but the crews would not have been soldiers but sailors from the Levant, a force than would always have a certain number – you can’t easily train ship’s crews within a short time. You have to work with what you already have: building warships is one thing, but training as many new crews is quite another. A number of 300.000 seems excessive. If they had numbers like these, they would have crushed the Greek navies due to vastly superior numbers alone.

I agree. As far as the Persian crews are concerned they were indeed trained men in their trade. You seem to believe that these ships were manned and trained by the Persians. They were not. There was not a single ship with Persian crew. They were all provided by their dependencies and were manned by adequately trained men. The list Herodot provides is very plausible :

300 Phoenician and Syrian ships.
200 Egyptian ships
150 Cyprian ships
100 Cilician ships
100 Ionian ships
100 Pontic ships
70 Carian ships
60 Aeolian ships
50 Lycian ships
30 Pamphylian ships
30 Dorian ships
17 Cycladian ships

None of the above numbers are improbable and room for more ships in Asia is of course aplenty, in my opinion. Fielding ships was never a problem, manning them was. Each of the listed Achaemenid dominions certainly had the manpower to do so. Combat experience, trained officers and knowledge of Greek waters is another thing. Training and combat experience, knowledge of tactics and generalship were in this era of great importance. 1,200 ships could even up the odds a bit, much less than that would have been easy prey, in my opinion, for the Greeks. The ships were fast, naval battles did not resemble those of the later Roman times. Knowledge of the waters was very crucial, since winds, currents, reefs, "hidden" bays and availability of safe harbors played a much greater role than normal circumstances on land. The Persians were quite aware of the Greek superiority and they also feared the loyalty of their own troops, just see how many of the ships in the Persian army are actually Greek! How probable would you consider that Xerxes would ever have set out on a campaign where supply by the sea was crucial if he didn't feel some kind of security in his fleet? Had he only half that many ships of which 1/3 would be manned by Greeks, that would only leave him with 400 triremes of questionable quality and 200 of questionable loyalty against a comparable in number and superior in quality and experience Greek navy. Should the Greeks in his own fleet hold back, the Athenians alone would have had the upper hand.

And is exactly the question. Back to the question asked before – where is that superior Persian organization that could feed armies twice the size of the entire Roman army at it’s highest estimate? Indeed, if the Persian empire ever counted as many as 50 million inhabitants it could probably feed them, and that they an administration worthy of their salt is also a given. But that’s not the same as fielding a million men and feeding them by sea and land. Napoleon tried to do that with a force of 600.000 in the early 19th century and failed miserably. I just don’t see that the Persians, essentially a tribal kingdom fresh out of the bronze Age, succeeded in a much, much more complex operation with a vastly larger force where the French, quite adapt at these operations, failed.

I personally think that the population of the Persian Empire was much larger than 50 mil, even though this is the number often quoted. Nevertheless, I think that in reality, the Achaemenid endeavor would have been better organized and easier to support than that of Napoleon against Russia. I do, personally, believe that the sophistication of these times is grossly underestimated and I do think that ships make all the difference. Had Napoleon the ability to safely support his army through the Baltic in a single march against Petersburg, what would be more similar to the Persian campaign, had he enjoyed uncontested naval superiority, then I do not see how he could have failed to get there and back with no problems regarding provisions whatsoever. Even with abundant supplies in his depots in Poland, Napoleon had no effective means to get them to the front.As I stated in my very first post, ships actually make all the difference.