Well, yes... I was playing arco. I attacked with my virtue, 300 odd myrmidons, and about 30 assorted mages, mostly mystics. My main force was ~70 wind riders.
Dominion 10!
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Unus vocis. Unus manus. Unus Universitas. Unus Deus. Is est meus fatum praeeo pro totus populus.
Ut est meus fortuna.
Armies of more than 500 soldiers are current in my game on Orania (I'm about turn 100 against mighty AIs). I think I have at least one or two big blob armies on my fronteers (or rampaging in my dominion) since 20 or so turns. The biggest I've seen was an army of 900+ from Ct'is, half lizards half undead and including about 50 chariots. My EA Ermor own a big third of the map but 2 of the 6 remaining AIs still have more troops than me.