I am open to reinterpreting classic myths and legends in different settings. For example, it their "Elseworld" stories DC comics has retold the familiar origins of Superman and Batman in different time periods: e.g., Superman arrives in the England of the Dark Ages or Batman in the London of Victorian England. For that matter, "Camelot 3000" has Arthur and the knights of his roundtable reincarnated in the year 3000 in time to save England from an alien invasion. So when "King Arthur" wants to locate the "true story" of Arthur in the last days of the Roman occupation of Brittania I find that to be an intriguing idea.
The Romans had always found this last outpost of the Empire a problematic area: Hadrian's Wall essentially separates the north (Scotland) from the south (England), trying to keep the Woads (Huh? We would get the wrong idea if you called these people the Celts?) on the other side of the barrier. Adding to the incentive to abandon the land is the arrival of the Saxons on the scene who are set on killing everyone and pillaging everything. In such a land, a man who could become a rallying point against the onslaught of barbarism would be worth remembering.
In David Franzoni's script Arthur (Clive Owen) is the son of a Roman officer and a Briton woman. Sent to Rome to be educated he returned as Arturius, commander of a garrison on Hadrian's well. His knights, in a subplot that does come across as a bit forced, are from the land of Sarmatia, far to the west. When their land was defeated the Romans spared their lives, but bound the knights and their male descendants to 15 years of military service. Now that period is up and awaiting their honorable discharges (and safe passage throughout the empire) are the last six of the Sarmatia knights who ride with Arthur: Lancelot (Ioan Gruffudd), Tristan (Mads Mikkelsen), Gawain (Joel Edgerton), Galahad (Hugh Dancy), Bors (Ray Winstone) and Dagonet (Ray Stevenson). They just want to go home, but a bishop (Ivano Marescotti) shows up from Rome with one last mission.
The knights go, but it is not for the bishop, because they are all pagans, or for Rome, because they care little for an empire that is abandoning the land their friends died defending, but for Arthur. The only one who does not seem to know that he is a living legend is Arthur himself; or, if he knows, he neither cares nor believes in the stories. But Merlin (Stephen Dillane), the holy man of the Woads respects Arthur as the warrior who can lead men in battle, Cerdic (Stellan Skarsgård) the leader of the Saxons hears Arthur's name everywhere he goes and finds him the rare man worth killing, and young Guinevere (Keira Knightley) has been raised on fairy tales about Arthur and his knights. This film is not about King Arthur as much as it is about how Arthur became king in this reimagining of the tale.
Given the context of this telling of the Arthur story it makes sense that the epic love triangle between Arthur, Guenivere and Lancelot is jettisoned. In many ways that story, which remains the greatest love triangle since it is the husband's wife and best friend, has taken over the Arthurian legend. Director Antoine Fuqua is really going back to the basics, although in a way that will make most Arthurian scholars cringe. In this context I like not only turning Guenivere into a Celtic warrior but also that she advocates Arthur's destiny and is not merely a landed lady worthy of marriage. Besides, there is the nice contrast between Knightley's stately beauty as she fires her arrows and her ferocity as she gets to race across a battle field and win a bunch of sword fights. You get the feeling she was having the most fun of anyone in this film (I waited patiently for Ioan Gruffudd to do something really impressive with his two swords but they never really came up with anything).
What is interesting given the idea that the Knights of the Round Table were the personification of Christian warriors is how the Church is blamed in the film for the downfall of Rome. Arthur is a true believer who has taken the teachings of Christianity to the level of the equality of all human beings, while the only other Christians we see in the film are engaging in torture and slavery. Arthur embodies the best of both Roman and Christian virtues, which makes him a most unique individual, but this film really does some serious retroactive Church bashing.
Yes, there are some problematic elements in this film. No Roman family, let along one with the Pope's favorite godson, is going to be living beyond Hadrian's Wall in Caledonia (Scotland), and I the ending of the sword fight between Arthur and Cerdic is so trite by this point in movie history it is rather insulting to the audience. But on balance this is ambitious effort to tell the "real" story and there the situation is reasonably well thought out (plus working in bits from classic films like "The Seven Samurai" and "Alexander Nevsky"). Most importantly, the actors make it believable, even when they have to proclaim rather pretentious dialogue. The climactic battle scene offers a nice blend of Roman technology and Celtic bravery (I thought the charge of the Woads was a nice representation of the speed of the Celtic attack since they do not bother with armor), and the result, while not a great film, is certainly interesting enough to warrant a look.