What is the origin of Bretagne?

Bretagne, or Brittany, is a region in northwest France that has its roots in the ancient Celtic culture. It was settled by Celtic tribes, particularly the Britons, who migrated from Britain around the 5th and 6th centuries AD, leading to its distinct language and traditions. The name "Bretagne" is derived from "Britannia," reflecting its historical connections to the British Isles. Over the centuries, it has maintained a unique cultural identity, influenced by its geography and history, including its ties to both France and the Celtic world.