Playing extremely fast and loose with history, this takes place just after the signing of the Magna Carta, which was apparently some kind of 13th century Occupy movement, and has King John (Giamatti) taking out the signatories in an attempt to regain power. The rebels have help on the way from the French, but need to hold Rochester Castle to prevent John from securing the entire region. A small band of soldiers, under William d'Aubigny (Cox), and led by the Knight Templar Thomas Marshall (Purefoy), have to withstand a siege by the King and his army of Hungarian-speaking Danish mercenaries - no, I'm not kidding - until the French allies can arrive. They can then help depose John, and England is then ruled by the French for tne next hund... No, wait, what? Didn't actually happen like that? Well, as we all known, when the facts do not conform with the cinematic storyline, then they must be disposed of.
Which actually works pretty well in the first half, with Purefoy cutting an impressively bad-ass figure, while English (the director, not the race) heaps on the gore, to an almost Spartacus-like level. However, when the blood stops flowing, things are a lot less interesting, most of the characters lacking in depth, which results in one-note performances from a good cast of actors whom we largely know to be capable of much better. There's also an irritatingly pointless and entirely clichéd subplot involving a forbidden love-affair between Marshall and the lady of the castle (Mara, sister of the Girl With The Dragon Tattoo). It'd have been nice if John had kidnapped and tortured her for a bit. And by "for a bit," I'm thinking the rest of the movie. I haven't seen such an annoying medieval bint since Shannyn Sossamon in A Knight's Tale. 20 minutes less of this - ideally, obtained by excising her scenes - and this would be a great deal improved.