Bret Devereaux

But the Romans were still militarily strong thanks to tough semi civilized recruits like the Illyrians while the Han strategy was basically use the barbarians to fight the barbarians. I think the general trope(for pre-moderns) holds up well.

You'll have to forgive me for being a touch brusque, but no. The armies with which the Romans conquered Sicily, North Africa, Spain, Greece, Gaul, Illyria, Anatolia, Syria, Egypt, inter alia, were made of two groups of Italian peasants: with Roman citizenship and without.

The army of the imperial period was half Roman citizens and half auxiliaries, but many of those auxiliaries were recruited from the posh, civilized parts of the empire. Archers from Crete is the standard example.

As for the Han Chinese, while yes, they recruited auxiliaries from everywhere, the core of the army, as I understand it, remained the ethnically Han professional infantry, which was still the core of the army when the dynasty collapsed.

This is where the popular conception of these armies drives me nuts. I have a damned doctorate in the Roman army and yet often I cannot recognize it in the descriptions of it that I get from laypeople. They describe a military force that is unfamiliar to me.