Ancient army numbers

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...I don't think the Persians meant to destroy all of Greece and leave a wasteland.

If you look at the losses of the Grande Armee of Napoleon during the summer of 1812 (the winter losses were quite another matter), we can't expect armies of this size to travel such distances without a proper logistical system and not expect dreadful losses. Smaller armies (and I think that, say, 60.000 would still be a fairly large force), would stand a much better cjance of remaining intact.
How large were the largest Roman expeditionary armies?

Seems we picked the same comparable example Robert (although mine does refer to the winter campaign). But did both army commanders expect a quick strike and not expect their logistic "tail" to end up wagging the front line dog?