Inspired by the opening of Tutankhamun's tomb in 1922 and the Curse of the Pharaohs, producer Carl Laemmle Jr. commissioned story editor Richard Schayer to find a novel to form a basis for an Egyptian-themed horror film, just as the novels "Dracula" and "Frankenstein" inspired their 1931 films "Dracula" and "Frankenstein". Schayer found none, although the plot bears a strong resemblance to a short story by Arthur Conan Doyle entitled "The Ring of Thoth". Schayer and writer Nina Wilcox Putnam learned about Alessandro Cagliostro and wrote a nine-page treatment entitled "Cagliostro". The story, set in San Francisco, was about a 3,000-year-old magician who survives by injecting nitrates.