Food supplies during Persian War

[Aryaman2]

But conscidering that your average Greek confederation like Phokic, Beotian, Locrian could easily field 15000 to 25000 heavy and light infantry and 300 to 500 cavalry, I find hard to swallow that Xerxes tried to conquer Greece with 25000.

But where did you get those figures for Greek confederation, are they any more reliable than Herodotus?