It’s interesting to see other characters added to the Arthur legend as time passes. For example, Lancelot was a French creation from centuries after the original story.
I view Arthur as a composite character, repurposed for different agendas at different times. If there were surviving pre-Roman sources, I’d not be surprised to see him there. No telling when the name started.
Here’s an old FReepmail I sent to someone in April of last year:
There must have been some kind of patchwork of post-Roman kingdoms of which very little remains in contemporary writing. My guess is, the Roman Hadrian’s Wall, and the two “dark age” earthworks, so-called Offa’s Dyke (it’s certainly much older than Offa), and the Wansdyke, probably represent the north, west, and south borders of some political entity.
The “Arthur” that wound up being part of childhood literature in the English-speaking world is a recent invention. The name Camelot is certainly a corruption of Camulodunum, modern Colchester, and may or may not have been its capital, but clearly such a naked coastline must have been important to such a post-Roman state.
[Alternatively,] The Car Dyke, the 80+ mile Roman-era canal, may have been the eastern border, however.
“It’s interesting to see other characters added to the Arthur legend as time passes.”
I told bedtime stories for my kids about King Arthur and the Knights of the round table. Other characters that I added over the years were Superman, Batman, Cinderella, Bigfoot....