Kind of confusing ain’t it.My recollection is @ 870AD.
I read a very convincing book ,hose title and author escape me, that posited two Arthurs one the other’s grandson. They are both historical characters and the Arthurian tales, the more credible ones, place Artur in two conflated cultural periods, one with Arthur as a Romanized British king during the later stage of the Roman Empire and the grandson as king fighting the Saxons a few centuries later. That author in his peregrinations found evidence of both in Southwest England and Wales. Now I want to find that book again.