A number of mainland Europe tribes that invaded the British Isles between 1000 and 500 B.C. The Celts settled throughout the Isles and eventually became the races known as Britons, Welsh, Scots, Irish, and Cornish.

Control of the British Isles was taken from the Celtic tribes when the Romans invaded in the first century. The Celts known as the Britons, who inhabited the southern half of the island, became "Romanized" and were thus left as the ruling race after the Romans withdrew. Arthur is often represented as a member (leader) of this race.

However, the term Celt must be regarded as linguistic and cultural, rather than racial.