The original version included a closing shot after Caligula has cut the fetus from Drusilla's womb, which was considered very shocking. It was therefore re-edited several times, even on the day of its premiere, by order of Bill Slater, then Head of Serials Department. After initial broadcast and a rerun two days later, the scene was edited again, so that the episode is now "somewhat attenuated". The "slightly nastier version" of the episode's closing (a scene that used "makeup on her belly") was only shown twice in 1976 and is now lost since the BBC no longer has a copy of it. Jack Pulman noted that the original script for the episode ended with "a long shot showing the butchered woman hanging on a chariot".
Drusilla did not die from Caligula's hand. Rather she died from the same fever that had made Caligula ill. Caligula was so distraught that he refused to leave her bedside even after she'd died.
This episode takes place from 37 to 38 AD.
Helen Mirren was offered the role of Julia Drusilla, but declined as she was busy filming The Collection (1976) with Malcolm McDowell. They starred in Caligula (1979), which was also about ancient Rome (McDowell played Caligula and Mirren played Caesonia and Teresa Ann Savoy played Drusilla).