Cornish

The Cornish, who call themselves Kernowyon, are the Brittonic people of the south-western peninsula, heirs of Dumnonia's Dumnonii. Cut off from the Welsh by the Saxon victory at Deorham, they kept their Brythonic speech, almost mutually intelligible with Breton. Athelstan fixed the Tamar border in 936; by the late tenth century Cornwall had been incorporated into the English kingdom, keeping its own language and customs.

Tin mining shaped life through Stannary courts and parliaments under royal privilege, and in 1337 Edward III made the earldom a duchy for his son the Black Prince.

English advance met resistance: the 1497 rebellion under Michael An Gof and the 1549 Prayer Book Rebellion, whose defeat broke Cornish as a community language. Dolly Pentreath, popularly its last monolingual speaker, died in 1777; Methodist chapels sustained their identity and miners carried their craft abroad.