> I have absolutely had well-meaning people quite confidently inform me that Roman military strength was a consequence of their cultural and ethnic cohesiveness.

... Wait, how? I mean, I think popular culture _does_ generally gloss over the Italy-is-not-Roman dynamic, but movies and so on often depict auxiliaries. And certainly anyone who looked at the history would struggle to come to this conclusion.

Maybe those people literally _are_ basing their knowledge of Rome on Age of Empires!

(The Civ games eventually kind of figured this dynamic out; there are independent small nations which you can subjugate, though the subjugation is often fairly... whitewashed, and may consist solely of sending them a bunch of embassies.)