Well, they never really did defeat all of us. For example in my own valley there wasn't a single pizza joint here until the 20th century. Why? It's simple. The steep sided valley was full of swamp and nasty animals, and the hilltops were full of nasty locals and lots of boulders which could easily be rolled down on incoming latins and their Gallic mates. The nasty animals seem to have died out now, but we kept the boulders handy till the end of the Cold War.