Twice jailed for drug use, Jay Robinson once had the dubious honor of being recognized by his fellow inmates when this film was played for the convicts.
The set of the Christian neighborhood in Rome has previously been used in The Robe (1953) (of which this film is the sequel) as the village of Cana. We can easily recognize the well with old broken columns.
According to Jay Robinson (Caligula), the break in principal photography between The Robe (1953) and this film was only three weeks. This would account for "The Robe"'s opening shot of the gladiatorial arena, a scene lifted from its sequel. The scene features Victor Mature and Robinson, in addition to Ernest Borgnine, William Marshall, Richard Egan and Susan Hayward; these last four were not in "The Robe".
Victor Mature and Richard Egan, who played enemies in this movie, would play close friends in the film noir melodrama "Violent Saturday" the following year.
A close-up view of one tiger growling shows that its top canines were removed.