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

[Jim Webster]

Work on the presumption Xerxes had all the figures we have discussed here and knows it is not a good idea to starve his vassal states to death (it make them disgruntled and rebellious). He can feed his engineers by sea during the 4 years they work at the canal, etc. The Thasians import food, fine, the point is their economy is sufficient to feed them and spare 4,4% for a transient Persian army. Bear in mind the meal cost them 400 talents. Their mines made them between 200 and 300 talents of silver a year, so 4 years is adequate time to store up enough lucre to do some serious buying in preparation for the arrival of the Persian host (and I doubt they bought all their own food from their silver).

Xerxes (or his people) would have the figures, they'd have people who could look at the land as they rode through and make a pretty good assessment. 
Buying food locally for the engineers might actually be good 'PR' in that it creates a market and encourages production. Paying a little over the odds locally might make for happy subjects (and still be cheaper than too much in boats.
The Thasians were apparently known for their wine and oil, so I suspect that their exports could cover a lot of imports.
The advantage the Thasians would have is that if they were major grain importers for their own use, they'd have the facilities to be able to cope and produce the extra meal. They could just have bought grain from Egypt from the early harvest in April/May.

[Jim Webster]

I do not wish to disturb a positive line of discussion, but do want to sort out one point.

Patrick please be sensible

A community doesn't just hand over its entire food stocks. They are merely condemning themselves to slow, lingering and unpleasant death.

Herodotus mentions grinding corn for 'many months' into flour.  This indicates that as of early spring they had 'many months' of corn available to grind.  Whether this was their entire stock is another matter - probably not, because as you rightly point out Herodotus does not mention mass starvation among the local population (although the returning Persian army is subject to mass starvation).

You do not store flour for many months, it goes off. That's why armies issue troops grain and let them grind it themselves.
This might have been flour for the detachments already there. By definition they were not making flour for troops who wouldn't eat it for another three or four months

[Jim Webster]

Everything I have read about this (5th century BC) period convinces me these are not subsistence economies;

seriously, read something about ancient Greek agriculture
Also just to try and put these things into perspective. If you had the land to produce eight tons of wheat, in Athens that made you wealthy enough to be a hoplite.
You know those grain trailers you can end up following through Lincolnshire or the eastern counties in summer. Eight tons isn't going to fill one.
These people were subsistence farmers. Most hoplites cultivated their own land with their own family and perhaps a slave or two. They were the wealthy ones who almost certainly had some to sell. The rest, the smaller farmers, would rarely sell wheat, because they never had enough surplus. They made any cash from selling vegetables, olives and suchlike when they had a good year.

[Duncan Head]

To support Patrick's point about Greek poleis maintaining stockpiles of surplus grain, here's an anecdote from (pseudo-)Aristotle's Economics II:

The people of Selymbria had a law, passed in time of famine, which forbade the export of grain. On one occasion, however, they were in need of funds; and as they possessed large stores of grain, they passed a resolution that citizens should deliver up their corn to the polis at the regular fixed price, each retaining for himself a year's supply. They then granted right of export to any who desired it, fixing what they deemed a suitable price.

Not dated, unfortunately. Selymbria is on the Thracian coast, west of Byzantium.

[Jim Webster]

To support Patrick's point about Greek poleis maintaining stockpiles of surplus grain, here's an anecdote from (pseudo-)Aristotle's Economics II:

The people of Selymbria had a law, passed in time of famine, which forbade the export of grain. On one occasion, however, they were in need of funds; and as they possessed large stores of grain, they passed a resolution that citizens should deliver up their corn to the polis at the regular fixed price, each retaining for himself a year's supply. They then granted right of export to any who desired it, fixing what they deemed a suitable price.

Not dated, unfortunately. Selymbria is on the Thracian coast, west of Byzantium.

the year's supply is what will carry them through to the next harvest, the extra would be whatever surplus the farmer would sell anyway.
A lot of Greek cities had laws forbidding the export of grain. Athens had at various times laws saying that any ship that entered the harbour with grain had to sell it. With cities perpetually on the edge of famine, these rules were important and policed.

So in the case of Selymbria, like a lot of cities they don't allow the export. They'd store grain, buying the surplus from their citizens every year, and every year they'd sell out of store to their citizens who didn't have their own grain. This allows the rotation of stocks and means that you rarely have 'old grain' lying about. If there was a poor harvest then the city could run the stock down.
(A bit like the intervention buying policy of the EU)
Finally after a number of good years, the city has got more grain that it needs so it'll sell the grain to anybody from abroad who wanted to buy it.

[Justin Swanton]

Stepping back a bit to get some perspective, Xerxes taking an army of several million into Greece is a crazy idea, even if it can be shown to be logistically feasible, so I understand an instinctive disinclination to believe it. My own take is that after his father's first campaign failed Xerxes raised the stakes. Estimates from the primary sources put the army of Darius I at between 200 000 and 600 000 men. Working on the notion that Persians used huge numbers to intimidate enemies into submission and that Darius' army hadn't been big enough - in Persian eyes - for the job, Xerxes' solution was to increase its size fivefold or more.

But it's still crazy to put millions of men at the end of a fragile supply network that depended on good weather and the Greek fleet being overcome. It's up there with Hitler declaring war on the US just as the German army ground to a halt in Russia. Thinking about it, I see quite a bit in common between Xerxes and Hitler. They both had grandiose ideas and possessed capable and docile subordinates and powerful state machinery to carry them out, but they were fundamentally out of touch with reality.

[Mark G]

And back to the nazis again.

Incredible

[Jim Webster]

capable and docile subordinates and powerful state machinery to carry them out, but they were fundamentally out of touch with reality.

I'm not sure how powerful the state machinery was or how docile the subordinates were.

Cyrus was the founder and fought all his life so we can set him aside.
Cambyses seems to have inherited the empire smoothly enough, but whilst he was campaigning in Egypt the throne was seized by Bardiya who might or might not have been his brother and Cambyses dies 'in disputed circumstances', perhaps assassinated by either the supporters of Bardiya or Darius who went on to challenge Bardiya
Bardiya might have been the brother of Cambyses whom Cambyses had had secretly murdered and then the identity was stolen by an imposter who seized power, or he might have been the brother who seized power. He ruled for about a year
Darius seized power from Bardiya, perhaps legitimately, perhaps not. He spent the first year or so putting down revolts around the Empire. After the defeat of his invasion of Greece there was a revolt in Egypt and died before he could lead his army to put down the revolt.
Xerxes followed his father and crushed rebellions in Egypt and Babylonia. Then he had to go back and crush at least one more rebellion  in Babylonia.
Finally he led his army to Greece, lost and fifteen years later died in a complicated palace coup where his family only retained power by the skin of their teeth.


I must admit I'd suggest that Xerxes might even have been the opposite. He could have demanded small token contingents from the various satrapies, drawn from their military and political elite (They probably didn't need to be any more than a thousand or so strong) more as hostages, to limit the chance of more revolts springing up behind them.
The State machinery wasn't powerful as we would see it. The power lay in the ability of the Great King to keep the loyalty of the core army of the Medes and the Persians, and in the ability of that army to crush any revolt that broke out.

The subordinates were not docile. Only one of the Kings named died in his own bed of natural causes, three were assassinated or murdered by the winner in a coup 

[Patrick Waterson]

A lot of Greek cities had laws forbidding the export of grain. Athens had at various times laws saying that any ship that entered the harbour with grain had to sell it. With cities perpetually on the edge of famine, these rules were important and policed.

But were cities 'perpetually on the edge of famine'?  There are a number of long sieges in Thucydides.  Discounting Plataea, which sent away most of the population in advance, we have Samos (440-439, nine months) Potidaea (432-430/429, about two years), Mitylene (428-427 BC), Melos (416 BC or 416-15 BC, depending upon whom you read), Syracuse (415-414 then re-established briefly in 413) and even Athens, famously dependent upon imported corn, held out for several months from 405 to 404 BC.

While the last few weeks of a siege usually saw the population surviving on very reduced and/or improvised rations, the fact is that Greek cities had stocks which lasted them many months and in some cases a few years.  This is not living 'on the edge of famine', and cities such as Sybaris in Sicily gained a reputation for exactly the opposite: a life of abundance.

[Patrick Waterson]

capable and docile subordinates and powerful state machinery to carry them out, but they were fundamentally out of touch with reality.

I'm not sure how powerful the state machinery was or how docile the subordinates were.

We can probably allow Xerxes' subordinates a reasonable degree of docility until things start to go wrong.

He succeeded to the throne without fuss, crushed national risings without serious difficulty, mustered the greatest-ever mobilisation in Achaemenid history without fuss (beyond the sheer effort of getting it done) and bestrode the world like a colossus, secure in his supreme power, punishing with impunity acts of disloyalty (like grandees who wanted at least one of their sons to stay at home) and even chastising the Hellespont when it disobeyed him.  None of this would have been lost on his subordinates, nor the rewards for those who pleased him.

I must admit I'd suggest that Xerxes might even have been the opposite. He could have demanded small token contingents from the various satrapies, drawn from their military and political elite (They probably didn't need to be any more than a thousand or so strong) more as hostages, to limit the chance of more revolts springing up behind them.
The State machinery wasn't powerful as we would see it.

It was nevertheless highly pervasive.  An extensive bureaucracy was backed up by the King's Eyes and a still-present sense of Persian supremacy and the mentality was still that of a successful outward-looking empire; the satrapal rebellions (as opposed to national risings) did not begin until the Empire was locked into itself following the failure of Xerxes' expedition, the devastating Greek reprise under Cimon and the Egyptian revolts.  And while Xerxes could have limited himself to 'hostage contingents' (and the concomitant problem of ambitious stay-behinds raising a revolt now that all of their rivals were at the King's mercy) his vanity would have demanded nothing less than a full mobilisation.  A king who wipes out a whole family because one of them wants to stay behind is not going to be satisfied with token contingents from anyone.

The power lay in the ability of the Great King to keep the loyalty of the core army of the Medes and the Persians, and in the ability of that army to crush any revolt that broke out.

There was of course much more to it than that.  Satraps were appointed for loyalty, influential nobles rewarded when they pleased the King of Kings and punished when they displeased him, and the whole business was as much about anatomy and minds as Medo-Persian force.  It may be worth noting that when, later in the dynasty, rebellions did occur, the task of suppressing them was customarily given to another satrap and did not necessarily involve the bulk of the core Medo-Persian forces.  Of course by then mercenary Greeks had replaced the Medes and Persians as the cutting edge of Achaemenid forces, and Achaemenid control seems to have centred as much on manipulating the Greek cities as anything else.

[Jim Webster]

A lot of Greek cities had laws forbidding the export of grain. Athens had at various times laws saying that any ship that entered the harbour with grain had to sell it. With cities perpetually on the edge of famine, these rules were important and policed.

But were cities 'perpetually on the edge of famine'?  There are a number of long sieges in Thucydides.  Discounting Plataea, which sent away most of the population in advance, we have Samos (440-439, nine months) Potidaea (432-430/429, about two years), Mitylene (428-427 BC), Melos (416 BC or 416-15 BC, depending upon whom you read), Syracuse (415-414 then re-established briefly in 413) and even Athens, famously dependent upon imported corn, held out for several months from 405 to 404 BC.

While the last few weeks of a siege usually saw the population surviving on very reduced and/or improvised rations, the fact is that Greek cities had stocks which lasted them many months and in some cases a few years.  This is not living 'on the edge of famine', and cities such as Sybaris in Sicily gained a reputation for exactly the opposite: a life of abundance.

Any siege that starts after harvest is by definition going to find the inhabitants with enough grain to get through to the next harvest. Please I'm embarrassed at having to write this.
If you want to discuss individual sieges then we can start a separate thread, and look in each one in detail.
The reason Greek cities did attempt to stockpile grain was because they lived on the edge of famine. One bad harvest for an inland city could lead to drastic consequences. The stockpiles would rise and fall. This is standard stuff, early on I recommended a book on the grain trade in the ancient world. There are plenty of excellent books discussing Ancient Greek agriculture (as well as Agriculture in the ancient world generally.) It's a well researched area.

[Jim Webster]

capable and docile subordinates and powerful state machinery to carry them out, but they were fundamentally out of touch with reality.

I'm not sure how powerful the state machinery was or how docile the subordinates were.

We can probably allow Xerxes' subordinates a reasonable degree of docility until things start to go wrong.

He succeeded to the throne without fuss, crushed national risings without serious difficulty, mustered the greatest-ever mobilisation in Achaemenid history without fuss

stop right there. That is a circular argument. You cannot argue that the Persian Empire logistically supported an army several million strong by saying it had strong kings who mustered the greatest ever army in Persian history.

[Jim Webster]

I must admit I'd suggest that Xerxes might even have been the opposite. He could have demanded small token contingents from the various satrapies, drawn from their military and political elite (They probably didn't need to be any more than a thousand or so strong) more as hostages, to limit the chance of more revolts springing up behind them.
The State machinery wasn't powerful as we would see it.

It was nevertheless highly pervasive.  An extensive bureaucracy was backed up by the King's Eyes and a still-present sense of Persian supremacy and the mentality was still that of a successful outward-looking empire; the satrapal rebellions (as opposed to national risings)

Good, another milestone. This successful outward-looking empire had national rebellions. It had them regularly. Pretty well every King had to face them. They were the norm

[Jim Webster]

There was of course much more to it than that.  Satraps were appointed for loyalty, influential nobles rewarded when they pleased the King of Kings and punished when they displeased him,

And three of the five Persian Kings including Xerxes were murdered by influential nobles or family members. They were a group who had to be kept on side.
Only one Persian king in this period wasn't

[Jim Webster]

  It may be worth noting that when, later in the dynasty, rebellions did occur, the task of suppressing them was customarily given to another satrap and did not necessarily involve the bulk of the core Medo-Persian forces.  Of course by then mercenary Greeks had replaced the Medes and Persians as the cutting edge of Achaemenid forces, and Achaemenid control seems to have centred as much on manipulating the Greek cities as anything else.

I have made a point of ignoring the later Persian monarchs, because they cannot have had an impact on the thinking of Xerxes or why he took the army he did

But his successor Artaxerxes I was probably a success, in that he seized power in a coup, held in with only a few rebellions and probably died in his bed

His successor Xerxes II was assassinated after 45 days
His successor Sogdianus reigned for six months before being overthrown by his brother who executed him
Darius II took power in a coup and seems to have died of natural causes after a reign of 19 years
Artaxerxes II inherited the throne and immediately faced revolt from his brother Cyrus. He then lost Egypt but did defeat the Satraps revolt.
Artaxerxes III waded to the throne in blood, but the killing might have been done by his father to ensure the succession, finally put down the Egyptian revolt and may have died of natural causes or may have been murdered by  Bagoas, the  Vizier
Artaxerxes IV, raised to the throne by a coup plotted by Bagoas, and ended up being poisoned by Bagoas
Darius III  Killed Bagoas and ended up being murdered by Bessus, his cousin.

So of the first 5, one died in his bed and three were murdered, and one died in battle.
Of the next 8, 3 or 4 died of natural causes and 4 or 5 may have been murdered.

If you were Great King, King of Kings the one group of people you didn't trust was your family and the Persian aristocracy!