Watched The Celtic World by Jennifer Paxton from The Teaching Company, LLC.

Lecture 10: Celtic Britain after Rome
North and west of what today is England, where the Romans held far less influence, a paradoxical era of both peaceful immigration and rebellion added to the melting pot of Britain in the first millennium A.D. Discover Cornwall, Wales, and parts of Scotland with a quick appearance of one of Britain's noblest legends: King Arthur.

42% done
Assimilation of Germanic peoples in Britain in 5c.
Breedon on the hill translates to hill hill on the hill
By Tre, Pol, and Pen you shall know the Cornishmen
Discussion of disappearance of British and other languages in place of a growing English dominance. Resurgence of Cornish.