Could the Persian Empire logistically support an army several million strong?

[davidb]

I've been reading this thread with interest, and it just struck me that all of the arguments for the size are premised on a one way trip, and a total lack of enemies around the Persian empire. Xerxes is not going to take the entire Persian army on a one way trip. He will have to provision their journey back. We know that Mardonius asked for 300,000 men to stay with him to conquer the Greeks.

"Therefore, since the Persians are in no way to blame, be guided by me; if you are resolved not to remain, march homewards with the greater part of your army. It is for me, however, to enslave and deliver Hellas to you with three hundred thousand of your host whom I will choose." Herodotus 8.100.5

This would mean feeding millions of men on the way back to Persia.

Of course, defence of the empire would also be paramount to Xerxes. With bulk of the military aged men in Greece, the empire would be easy targets for large scale invasions and raids from Scythians and other outsiders, not to mention internal revolts by the subject races.

David

[Andreas Johansson]

With bulk of the military aged men in Greece, the empire would be easy targets for large scale invasions and raids from Scythians and other outsiders, not to mention internal revolts by the subject races.

We-ell, to play devil's advocate, it's commonly supposed that part of the reason Xerxes brought representatives of so many different subject peoples was that if the warrior elite of, say, Hyrkania was with him invading Greece, they weren't back home stirring up trouble in his absence. I do submit that removing half or so of the military age manpower of a province would render it incapable of revolt (not to mention resisting foreign invasion or feeding itself).

[Jim Webster]

With bulk of the military aged men in Greece, the empire would be easy targets for large scale invasions and raids from Scythians and other outsiders, not to mention internal revolts by the subject races.

We-ell, to play devil's advocate, it's commonly supposed that part of the reason Xerxes brought representatives of so many different subject peoples was that if the warrior elite of, say, Hyrkania was with him invading Greece, they weren't back home stirring up trouble in his absence. I do submit that removing half or so of the military age manpower of a province would render it incapable of revolt (not to mention resisting foreign invasion or feeding itself).

Having raised, armed and trained half of the manpower of a province, it's going to make it awfully difficult to get them to do what you want without asking them nicely 

[Erpingham]

He will have to provision their journey back.

I think we can assume that Xerxes expected the Greeks to give in confronted by his mighty forces.  He would then have supplied them off the land until he could sort out an orderly evacuation of those not required for garrison duty.  These, then, he would he evacuated back through Northern Greece, having restocked his depots.  However, failing to achieve a workable base and also loosing naval superiority scuppered his plans.

[Erpingham]

On a different tack, Askleipidotus affirms that the open file order of 2 cubits or 6 feet or 2 yards per file is natural, and doesn't have a special name. I used this open order when calculating the width of the hypothetical Persian column. Here is an article that establishes experimentally that people on average prefer about a metre of space between themselves and strangers or acquaintances (a little less for acquaintainces). Go to the tables on p585 (9 of 16). One more reason to respect the primary sources.

Interesting correlation there.  Did I miss someone disrespecting Askleipodotus?  Or are you advocating the principle that if there is a reliable figure in one ancient source, the figures in all the others are correct?  I don't see where you are going here.

BTW, you need to give thought to what spacing your units (presuming you have units ) have between them, both laterally and front to back.  Those pictures of the march through Zululand showed quite wide spacings.  I don't think we should think of them in serried ranks like a precursor to the Nuremberg rallies.  Unless you've abandoned the wide road and gone for Patrick's swarming model?

[Erpingham]

Even the cross-country bit is not so much of a supposition since there are a couple of sources showing a Persian army doing just that - sure, in one case the army is nearing the enemy but it's too far away to face any threat marching in column until it gets close.

Just a reminder that one of patrick's examples comes from a different Persian era 800 + years later.  I'm not going to rule out basic similarities but we should be careful.  If we are to take them as an example of Persian practice, we perhaps should also see what Maurice (the Byzantine one) says about their camp practices. Were they as organised as the Romans, for example?

The other "swarm" is advancing against the enemy isn't it (before Cunaxa?) rather than route marching across country?  It also seems to be crossing a wide flat plain.

[Justin Swanton]

On a different tack, Askleipidotus affirms that the open file order of 2 cubits or 6 feet or 2 yards per file is natural, and doesn't have a special name. I used this open order when calculating the width of the hypothetical Persian column. Here is an article that establishes experimentally that people on average prefer about a metre of space between themselves and strangers or acquaintances (a little less for acquaintainces). Go to the tables on p585 (9 of 16). One more reason to respect the primary sources.

Interesting correlation there.  Did I miss someone disrespecting Askleipodotus?  Or are you advocating the principle that if there is a reliable figure in one ancient source, the figures in all the others are correct?  I don't see where you are going here.

BTW, you need to give thought to what spacing your units (presuming you have units ) have between them, both laterally and front to back.  Those pictures of the march through Zululand showed quite wide spacings.  I don't think we should think of them in serried ranks like a precursor to the Nuremberg rallies.  Unless you've abandoned the wide road and gone for Patrick's swarming model?

I'm keeping pretty open-minded about it. The Asklepiodotus mention does serve to make a 600 yard wide avenue slightly more plausible in that if you put a bunch of people in an area and tell them to start moving that is the spacing they would tend to adopt.

I think one can forget entirely about ranks and files when talking of the Persian army on the move, though the Macedonians and Romans (Crassus' square) seemed to have managed cross-country hiking in very organised formations. I would think the wide road is a preferable option since it requires the least amount of land clearing and gets the entire army from camp to camp. The wide, non columnar advance also works if the land is not too difficult to traverse to begin with.

[Dangun]

Xerxes would be attempting, with a population supported by subsistence agriculture, something which countries with modern 20th century manufacturing economies struggled to achieve.

This is an important and fundamental point.
It should not be forgotten how utterly unprecedented Herodotus claim is.

A military mobilization of the size claimed by Herodotus would not happen until 1914 - more than two millennia later.
Relative to population size, as Jim suggests, it has probably never happened.
Relative to space, no military force so large has ever been pushed through such a small space in such a short time, at least until the invention of mass rail.

We are an order of magnitude higher than just about any precedent.

[Flaminpig0]

ork.

There is no evidence grain was transported by ship in amphorae, granted. Sacks or loose seems to be have been the standard method. I suggested that the grain from Egypt and the Mediterranean coastline could have been shipped in amphorae if the local Greeks could not manufacture enough in quantity, but on reflection it makes more sense to transplant the potters in Greece, have them make the amphorae there (if amphorae were used), and then just ship the grain loose or in sacks. Bear in mind you don't need a vast army of potters, just a few thousand. A potter can make 4 amphorae in a day. You would need 5000 - 6000 potters to make the necessary amphorae. 6000 potters x 4 amphorae a day x 250 days per year (I let them goof off for 4 months a year) x 4 years = 24 million amphorae, should be enough for storing the long-term grain. Given them just Sundays off and it's nearly 30 million amphorae.

Justin, are you aware of the concept of Occam's razor.

I am indeed. And....?

You don't think it is more likely that Herodotus was wrong about the size of the Persian army than the alternative hypothesis which relies on a lot of supposition  to make it even remotely plausible.

Not quite. Occam's razor means that the simplest explanation, requiring the fewest number of suppositions, is likely to be the right one.

In this discussion those advocating taking Herodotus at his word need show only that supporting and moving such a huge army is feasible.

Those who oppose Herodotus need to show not only that supporting and moving such a huge army is not feasible (which involves another range of suppositions), but must also make the assumption that a careful writer like Herodotus is wildly wrong on the biggest single fact of his account - the size of the Persian army. This makes for a rather complicated razor.

Oh, and how many suppositions have you made to support your hypothesis ?

Just one, that the Persian army marched cross-country. The rest was a feasibility study in economics and logistics where, taking the data we have, I try to demonstrate that the Persians could have done it (as opposed to actually did it) whereas my worthy opponents argue that they couldn't. But that's not making suppositions.

Even the cross-country bit is not so much of a supposition since there are a couple of sources showing a Persian army doing just that - sure, in one case the army is nearing the enemy but it's too far away to face any threat marching in column until it gets close.

Something else came to mind whilst thinking about the manuals: Asklepiodotus describes a whole variety of marching formations of which most do not involve following along a single track and many of those do not even involve keeping in column. It seems the Macedonian army at least was not the least bit bothered by marching off-road in nice, tight battle formations.

The feasibility study is full of suppositions from the methods of storage from grain, to the moving  of large numbers of potters to Greece, to doubling the population of the Persian Empire so  to make Xerxes army ever so slightly more believable etc.

[Patrick Waterson]

I think we can agree that the idea of an invasion force of six million produced by an empire with a population of 50 million is just silly and Herodotus, even if he didn't invent the figures, wrongly applied figures he'd found

Why?

In the first place, the standard calculation for fit men of military age is 20% of the population.  That makes 10 million out of 50 million.  Around 5 million (not 6) were utilised in the invasion. That is 10% of the population, the prime military age category.  And we need to get well away from any idea that the Achaemenid Empire was a subsistence economy - it was not!  It was the ruler of and heir to civilisations which habitually stocked up huge reserves of grain.  As an example, the first thing the Hebrews were set to doing when they received Egyptian citizen status in place of their previous guest status was to build store cities.

In the second place, these men are absent for a campaign - characteristically occupying the time span between sowing and harvest.  They are not subtracted from the economy for years at a time.  In 480 BC most of them would have missed the sowing - but how labour-intensive is that if one has already done the ploughing?  This is one thing women and children could help with and not prejudice their normal activities.

In the third place, the manpower drain is unequal.  The majority of the population is concentrated in the great breadbaskets of Mesopotamia and Egypt, but the fraction of the population conscripted from these areas seems minimal compared to the relatively heavy exactions from the less developed tribal areas.  In the latter, the overage men and below-age boys could manage the herds for a few months while the women get on with their gardens.

What would cause a problem is if large numbers of men failed to return.  This could have a severe impact on future years, and may well lie behind the feeble Persian activity in the 470's BC.  Rather than famine from lack of food, they would have suffered a manpower breakdown among the tribal satrapies, rendering them unable to provide effective military contingents.

[Flaminpig0]

  As an example, the first thing the Hebrews were set to doing when they received Egyptian citizen status in place of their previous guest status was to build store cities.

That is interesting what is the evidence for it?

[Patrick Waterson]

I've been reading this thread with interest, and it just struck me that all of the arguments for the size are premised on a one way trip, and a total lack of enemies around the Persian empire.

Which was pretty much the case in 480 BC.  Nobody was looking to invade it; everyone seems to have been holding their breath waiting for the outcome of Xerxes' and Carthage's invasion of Hellas.  But just in case there was a problem, given the 50 million population estimate, the stay-behind governors still had another 5 million (overage) potential conscripts scattered around the Empire to deal with adventurous intruders.

Xerxes is not going to take the entire Persian army on a one way trip. He will have to provision their journey back.

As earlier noted, and as Herodotus mentions, Xerxes thought the campaign would be a show of force with fighting an  optional extra.  With Greece subdued, he would have left a garrison (augmented by the not inconsiderable number of Greeks who had sent earth and water) and taken the bulk of the army back, supplied in much the same way as it had arrived, i.e. by the fleet.  Anthony pointed this out.  With regard to timing, it took Xerxes 45 days to get back to Asia without supply.  Going in and going out we are looking at a 90-day campaign, minimum, perhaps 120 days allowing for a month's worth of accumulated delays; stocking up for 180 days would have more than covered a leisurely invasion with room to spare.

This is an important and fundamental point.
It should not be forgotten how utterly unprecedented Herodotus claim is.

Which is precisely why Herodotus felt impelled to record what he could of it.  As for his comments, they are remarkably similar to yours.

"For full four years after the conquest of Egypt he was equipping his force and preparing all that was needed for it; before the fifth year was completed, he set forth on his march with the might of a great multitude. [2] This was by far the greatest of all expeditions that we know of. The one that Darius led against the Scythians is nothing compared to it; neither is the Scythian expedition when they burst into Media in pursuit of the Cimmerians and subdued and ruled almost all the upper lands of Asia (it was for this that Darius afterwards attempted to punish them). According to the reports, the expedition led by the sons of Atreus against Troy is also nothing by comparison; neither is the one of the Mysians and Teucrians which before the Trojan war crossed the Bosporus into Europe, subdued all the Thracians, and came down to the Ionian sea, marching southward as far as the river Peneus." - Herodotus VII.20

It is erroneous to assume that just because an event is unique, it never happened.

  As an example, the first thing the Hebrews were set to doing when they received Egyptian citizen status in place of their previous guest status was to build store cities.

That is interesting what is the evidence for it?

Exodus 1:11 and Manfred Bietak's excavations at el Daba.

[Duncan Head]

In the second place, these men are absent for a campaign - characteristically occupying the time span between sowing and harvest.  They are not subtracted from the economy for years at a time.

The dead ones are.

And this campaign lasted two years - 480 and 479 - whether Xerxes bargained on that or not. And some of the men surely are absent for years: how long does it take to march from India to Greece, fight a two-year campaign, and then march back? Assuming there were any Indians left to march home after Plataia, of course.

At the other end of the Empire, the Lydians were no doubt just out for a summer's walking holiday.

[Jim Webster]

In the second place, these men are absent for a campaign - characteristically occupying the time span between sowing and harvest.  They are not subtracted from the economy for years at a time.  In 480 BC most of them would have missed the sowing - but how labour-intensive is that if one has already done the ploughing?  This is one thing women and children could help with and not prejudice their normal activities.

Patrick, please, please learn a little about ancient agriculture, do you know how many times you had to plough? Also a lot of the troops from the Eastern Satrapies wintered in Sardis. They had to walk to get there. They could set off after the harvest but they'd have missed ploughing. So the ploughing had to be done. Sowing isn't just sprinking seed, there's field work necessary to create the tilth, which involves driven livestock and perhaps a plough, perhaps a harrow, and it involves rolling or whatever after sowing to aid establishment.
The battle of Salamis was fought in September. The troops from the Eastern Satrapies are going to struggle to get home in time for the next season's sowing.

[Jim Webster]

I think we can agree that the idea of an invasion force of six million produced by an empire with a population of 50 million is just silly and Herodotus, even if he didn't invent the figures, wrongly applied figures he'd found

Why?

In the first place, the standard calculation for fit men of military age is 20% of the population.  That makes 10 million out of 50 million.  Around 5 million (not 6) were utilised in the invasion. That is 10% of the population, the prime military age category.  And we need to get well away from any idea that the Achaemenid Empire was a subsistence economy - it was not!  It was the ruler of and heir to civilisations which habitually stocked up huge reserves of grain.  As an example, the first thing the Hebrews were set to doing when they received Egyptian citizen status in place of their previous guest status was to build store cities.

please show me a multiyear campaign which took 50% of the men of military age away from the country?

As for these fabulous huge reserves of grain, please show me the excavation of the massive granaries. Please show me some evidence rather than wild surmise.