The film was originally intended to be made after El Cid (1961) and to reunite Charlton Heston and Sophia Loren. The set for the Forum Romanum was being built when Heston rejected the script and expressed an interest in 55 Days at Peking (1963) instead. Samuel Bronston immediately ordered that the work on the Forum be stopped and the landscaping and foundation work be adapted for the Peking set. After filming, the Peking set was torn down and replaced by the Forum. If you look carefully, both sets share a very similar topography.