Persian Invasion of 480 BC - articles

[Sean Manning]

If the First Crusade could muster 100,000 volunteers in such a short timeframe in the 11th C and migrate them all the way to the Middle East from all over Europe, why couldn't Xerxes get say 500,000 together and take them to Greece, especially if he had years to plan and get ready supplies? By the time the entire First Crusade contingent had reached the Middle East their numbers, I understand, included 500,000 footmen on foreign soil.

What is your source for that? That sounds much higher than estimates I recall in sources like Smail's [i]Crusading Warfare[/'i]. Numbers in medieval sources need to be treated very cautiously for reasons discussed by me and Aryaman2 above.

If Xerxes' plans were widely known in the Persian Empire I woud imagine that all of his eligible subjects would be able to personally prepare over a few years for the likelihood of having to go. Given the First Crusade's 500,000 over one year, simple maths says that millions is not unattainable for Xerxes over say 5 years?

No, it isn't attainable. There is a limit to how much food can be brought to a marching column, moved in through a port, or stockpiled to feed an invasion. Adding more men doesn't help much, and for it to help at all you need to spread most of them out across the countryside, constantly fetching food and vulnerable to attack. I doubt there were five million people in Greece! Remember that a man can only carry about 20-30 days worth of food if he carries little else, so soldiers from most of the empire could have brought no food to Sardis.

Let us imagine an army marching ten abreast, at 600 per mile (so only 3 yards per row of men including space for their carts and pack animals), moving 3 mph. Let us assume they can march 10 hours per day. Then 180,000 (10*600*3*10) people can cross a point in a given day and move into camp. In practice, less men than this will be able to move between camps if we want the people in the rear to reach camp in time to feed themselves and their animals and so on. But this should give some idea of the reasons you can't move a million people in one column.