After principal filming was completed, Howard Hughes decided the film needed some extra sprucing up. He had Nicholas Ray shoot a "Vestal Virgin Bathing Sequence" which immediately ran afoul with censors and enraged producer Gabriel Pascal, amongst others. The sequence was eventually deleted from release prints.
Stock footage from the RKO film The Last Days of Pompeii (1935) was used in shots of the crowds filing into the Colosseum.
A fifteen-second clip from Cecil B. De Mille's 1932 epic "The Sign Of The Cross" was used in the film.
Harpo Marx was considered for the part of Androcles at one time. This would have been the first and only speaking role of Marx's career.