Julius Caesar, after conquering Gaul, got interested in Germany. He expressed this interest by building a bridge across the Rhine. Having done this in a mere 10 days — something engineers tell us can’t be done now — he took his legion of soldiers across the bridge, tramped around a bit, and then went back and dismantled the bridge.

This, according to the History Channel, made it pretty clear, even without Twitter, that the Romans were people to be reckoned with. “If we want to come and conquer you,” this said to everyone, “we bloody well can.”

I don’t how it was that I never learned this before now.