Christopher Lee has called it his favorite Hammer film.
Done at Christopher Lee's insistence that Hammer do a film based on a Wheatley fantasy novel.
The movie's US title was changed to "The Devil's Bride" because its original title made it sound much too much like a Western.
Hammer first wanted actor Gert Fröbe in the role of Mocata.
Leon Greene's voice was dubbed throughout the film by Patrick Allen, the real life husband of Sarah Lawson (Marie Eaton).
Mocata was based on Alistair Crowley in the original novel. Dennis Wheatley invited him to dinner for research purposes.
Scenes of this film were used in the 1982 video clip "The Number of the Beast" by UK heavy metal band Iron Maiden.
Patrick Allen also did the voiceover for the UK trailer of this film.
Released as the main feature on a double bill with Prehistoric Women (1967).
