> In the popular imagination? The Romans were conquering barbaric tribes that aren't worth talking about in detail, I think.

There was plenty of interaction, but the thing about those insignificant barbaric tribes is that they aren't worth conquering either.

And there's a simple rule that's obvious even in a superficial read of de bello gallico: don't cultivate wheat and the legions won't bother you.

It's my impression the Gallic Wars were more about building Julius Caesar's personality cult than anything else. Enriching his soldiers so they'd be loyal to him and winning the respect of Roman pyblic (hence the self-aggrandizing book written in Latin, not Greek.)

Few external wars haven't been fought for internal reasons

Now it’s cultivate nukes and the legions won’t bother you.