Ive seen it written that kingdoms of antiquity werent feudal societies, but is this just wrong or what? didn’t they also have nobles and peasants and warrior castes?
Well, it depends what kingdoms you’re talking about, but in general you should avoid drawing a straight line from say, Classical Greece to Medieval Europe and saying it’s all the same thing and ignoring this massive thing in the middle called the rise and fall of the Roman Empire.
The classical world didn’t really have feudal contracts between the nobility and the monarchy – armies were much more likely to be either recruited from the citizenry or professional mercenaries than a warrior caste who provide timed military service in return for land – or serfdom for that matter (instead, slavery dominated).