The last few years have brought plenty of vicious historical actioners to cinemas, including Centurion and Black Death. Ironclad purports a stronger historical accuracy than its competition, but it certainly doesn’t hold back on the brawn and body trauma. It’s overlong, but Ironclad provides a righteous jolt, working as a gritty work of period recreation and as a sword-swinging marathon of squirting blood and flying severed limbs.

The year is 1215 and King John (Paul Giamatti, wearing a Prince Valiant wig) has retreated into the expanse of England, looking to build an army and reclaim power lost when he was forced to sign the Magna Carta treaty. Witnessing his return is Marshall (James Purefoy), a noble member of the Knights Templar who wishes to keep the raging king contained. Teaming up with Albany (Brian Cox), the men set out to form a company of mercenaries and misanthropes (including Jason Flemyng and Mackenzie Crook), looking to head off King John at Rochester Castle, a pivotal area that unites the land. Holing up inside the fortress with Cornhill (Derek Jacobi) and his bride Isabel (Kate Mara), Marshall and the men prepare for battle, facing the wrath of King John and his heathen army.

Co-writer/director Jonathan English has a specific tenor of doom in mind with Ironclad, and he’s skilled enough to pull the considerable anguish off. The goal here is to plop the viewer in the middle of a war, watching as Marshall and his testy band of outsiders defend a castle from a man scorned, a focused royal who will stop at nothing to restore his rule, which he believes is a God-given position. It’s this combustible mixture of politics, religion, and savagery that drives the film forward, generating an intense feel for combat and honor, a tone that English has a firm grasp on for the majority of the motion picture.

Also in the film’s favor are the locations, which evoke a harsh land of castles and crummy weather, highlighting environments as beaten and scarred as the men who cross the land. Though not blessed with the largest budget, English conjures a commendable sensation of time and place, with a cast enthusiastically displaying their medieval costumes and weapons, happily raising hell and chewing scenery — Giamatti and Cox being primary hams, but in entertaining ways that help English unearth the epic feel of conflict he requires when the action takes a smoke break. Ironclad looks superb, gritty and spare, doing much with only moderate financial backing.

In keeping to era standards, Ironclad is extraordinarily violent, with an orgy of slashings and severings depicted to maintain intensity. Few punches are pulled once Marshall declares war on the crown, with English keeping an eyes-wide-open approach to the brutality of warfare (cruelly, some of the conflict is photographed with worthless instances of shaky-cam), watching as soldiers are chopped and stabbed in a most graphic manner. Gorehounds will delight. Less convincing is a romance of sorts between Marshall and Isabel, worked into the film to maintain a human element the violence threatens to erase. It’s too calculated, despite a commendable articulation of skirt-hiking lust from Purefoy and Mara.

With the standoff covering months of stasis and starvation, English extends Ironclad past its expiration date. After a rousing opener, the picture settles into a routine of exposition and conflict that weakens the overall pace. It limps to a conclusion, yet Ironclad sustains a convincing posture of heroism and self-defense. Though derivative, it remains hearty and vividly destructive to the final moments.