Michael Conrad's movie debut.
According to Jay Robinson (Caligula), the break in principal photography between The Robe and Demetrius and the Gladiators 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 featues Victor Mature & Jay Robinson. Also Ernest Borgnine, William Marshall, Richard Egan AND Susan Hayward; these last four were not in The Robe.
Average Shot Length and Median Shot Length = ~10 seconds.
The set of the Christian neighborhood in Rome has previously been used in The Robe (of which this film is the sequel) as the village of Cana. We can easily recognize the well with old broken columns.