A knight’s tale drunk on carnage, Ironclad is set around the battle for Rochester Castle in 1215, the age of Robin Hood. A disillusioned Knights Templar, Thomas Marshall (James Purefoy), William de Albany (Brian Cox), and their band of men hold out against a horde of Danish mercenaries led by King John (Paul Giamatti), determined to renege on the compromises of the Magna Carta and get his Divine Right back. Cox seems like he’s being held up by his perpetually arched eyebrow, while Purefoy’s dourly bearded performance is a shaky keystone for a movie. His drab underplaying is the general rule, making Giamatti’s insomniac-eyed mad monarch a welcome distraction, not chewing scenery so much as flecking it in spittle. Director Jonathan English’s combat scenes are pell-mell hack-ups, with inserts of steel cleaving through torsos and brain-pans guaranteed to please Deadliest Warrior aficionados. The reproduction of siege warfare is catnip for arms-and-armor geeks, but while Ironclad captures the casual cruelty and flesh-and-bone violence of the 13th century, it fails to do the same in the more intimate material set in the downtime between assaults. In sections detailing Marshall’s brooding faith, courtly passion with Kate Mara’s fair lady, and mentorship of Aneurin Barnard’s callow squire, English’s tapestry is decidedly faded.