Giamatti plays King John in the true story of a band of Knights Templar, led by James Purefoy, who resisted the king's siege of Rochester Castle in a historic 13th-century battle. Billed as "A Medieval Magnificent Seven," Ironclad co-stars Kate Mara, Brian Cox, Derek Jacobi, and Jason Flemyng.
The film is rated R "for strong graphic brutal battle sequences, and brief nudity."
Be warned: Nonstop sword-slashing, neck-slicing, blood-spraying violence ahead.
Ironclad hits U.S. theaters on July 8.