Now that I'm not at work I can do a little digging.
Seems like it depends on when the story was written (before or after the Romans arrived). The Welsh story (stories), Tomas Malory and T. H. White all seem to be on the same general track, but differ in the minutia. I've got to dig around in my library and find it, because le morte d'arthur is an excellent read. I'm 50% though Seven Against Thebes (as written, not a translation) and when I get through Antigone I'm going to need something that doesn't require a lot of brain cells. Although I must admit my reading skills are growing, I can read it much better now, but I don't think I'll ever be able to pronounce much of it correctly (the East Tennessee accent doesn't help any I'm sure).