Demetrius and the Gladiators was the sequel to The Robe, and though they were released several months apart, the films were shot at the same time. Based on characters originally conceived by Lloyd C. Douglas, the film stars Victor Mature as the title character, an ex-slave who embraced Christianity after being present at the Crucifixion. Thrown in jail for defending an elderly merchant from a sadistic Roman legionnaire, Demetrius is forced to attend gladiator school and fight in the arena for the amusement of the mad, debauched emperor Caligula (Jay Robinson, likewise repeating his performance in The Robe). The well-proportioned Demetrius attracts the attention of Messalina (Susan Hayward), the nymphomaniac wife of Caligula's would-be successor Claudius (Barry Jones). Briefly losing faith in Christ, Demetrius is saved from himself by the apostle Peter (Michael Rennie). Because of contractual complications, Demetrius and the Gladiators was released to television seven years before The Robe.
by Hal Erickson synopsis