The film is set during the Crusades and describes Godfrey of Bouillon's conquest of Jerusalem in 1099.

In ancient Rome, tyrannical Emperor Caligula is assassinated through the machinations of Messalina. She then makes a conquest of Marcus, who forces the Senate to name her husband, Claudius, as emperor. Messalina's wicked ways continue when she falls in love with Ennio, a slave. Ennio is also loved by Egyptian princess Mirit, but he loves neither of them, preferring the company of Ela, a Greek slave.