I like very much Clive Owen and I like Keira Knightley even more, but I hardly managed to finish watching this movie. The story is simply boring, dialogues are dull, action scenes are ridiculous, and the description of Saxons and Britons could as well come from Asterix comic book.
The idea was actually quite good - recent findings confirm that some Sarmatians cavalrymen served in Britannia at the end of Roman empire and some of them probably stayed there, marrying local women, converting to Christianity and joining the fight against the Saxon invaders. Their fighting style and the custom of worshiping God by praying to the swords planted in the ground could really be one of the origins of the myth of Excalibur and the Knights of the Round Table. But the idea was completely wasted by the nonsensical screenplay.
Also, the presentation of early Christian church, as a bunch of slavers and thugs is simply demeaning. The mention of Pelagius and his heresy is interesting, but serves only to further Christian bashing.
After choosing to introduce Inquisition in the history SEVEN HUNDRED years before its real appearance, the director also presented V century Saxons like some kind of Nazis, obsessed with an ideal of Germanic racial purity, which considering the mores of the age is simply a total absurdity.
But all of this I could forgive, if at least the beauty of Arthurian England was shown, the action scenes were good, if there were some interesting dialogues and at least some humour, some drama and some romance - but all those elements are missing in action...
Frankly, do not waste your money and your time - this movie is simply worthless.