Marketed as a more historically accurate version of the Camelot mythos than previous incarnations, King Arthur is a complicated hash of fact and fiction. Screenwriter David Franzoni and director Antoine Fuqua attempt to graft latter-day theories about Arthur's possible real-life identity as a Roman cavalryman named Artorious Castus (Clive Owen) onto the most famous elements of the beloved legend. The filmmakers preserve the existence of Guinevere (Keira Knightley) and Merlin (Stephen Dillane), this time as Woad tribal leaders at war on two fronts against the invading Saxons and retreating Romans. They endeavor to explain the close kinship among Artorious' followers by identifying them as Salmatian cavalrymen, an allegedly elite corps conflicted by opposing allegiances. And they delve into the religious, ethical, racial, political, and philosophical tensions between these various factions. As might be expected, explaining all of these complicated machinations requires an unfortunate amount of exposition, after which an audience may be too baffled to notice some gripping sequences, particularly a tense skirmish ingeniously executed across the cracking ice of a frozen lake. His previous script for Gladiator (2000) used history as an interesting backdrop for a wholly invented story, but here Franzoni's clever concept is hidebound by his effort to modulate his sources, with murky results.