It's true that screenwriter David Franzoni (Amistad, Gladiator) has discarded or downplayed the most romantic elements of the Arthurian legend — there's no quest for the Holy Grail, no Camelot, and Merlin is just
a weird old king instead of a sorcerer — but much of what he's put in his script comes from the oldest versions of the myth, not from new scholarship based on fresh archaeological findings.