The ‘real’ King Arthur is an amalgam of at least two historical figures from the 5th and 6th centuries for whom little information survives, spiced up with elements from British Celtic mythology that predate this era.
To say that there is new evidence that Arthur was Roman not Celtic is just silly. You could say there was someone called Artorius of whom stories contributed to the myth of King Arthur. There’s a big difference.
A lot of more recent, semi-historic Arthurian stories portray Arthur as a Romanised Celt or belonging to such a family after the Romans had left. I like this interpretation.
‘Mists of Avalon’, that someone mentioned is a good Arthurian story, but I prefer Mary Stewart’s trilogy ‘The Crystal Cave’, ‘The Hollow Hill’ and one I forget the name of, which tell the story of Merlin, and a sequel which follows Mordred. But the best modern Arthurian story, must be TH White’s Once and Future King. Another favourite of mine is the Arthurian detective novel ‘Idylls of the Queen’ which draws on a superb knowledge of Malory.
I used to be a huge fan of Arthurian myth and literature. I really should go and see the movie.