Isolation
Brittany, the region in the northwestern corner of present-day France, was settled with Britons and Gauls. The Celtic tradition survived in the region since it was isolated from the rest of France, and a lot of festivals and events can trave their origins back to Celtic times. A lot of French “Bretons” also happen to wear traditional Celtic hats called coiffes (meaning “hats of lace”), and about one-quarter of the region’s residents speak Breton, a Celtic language that’s similar to Welsh.
Conquer
Despite the fact that Caesar’s invasion of Britain wasn’t successful, the Romans eventually had a successful attack against the Britons after Caesar’s murder in the first century A.D. This pushed the Britons on the island west to Wales and Cornwall and north to Scotland. As it turns out, the Romans actually built Hadrian’s Wall near what is now the border between England and Scotland, in 120 A.D. The wall was meant to protect the Roman settlers from the Celts who had fled north.