the story were inspired by the Guy de Maupassant story "Fear" and Bram Stoker's Dracula. Bevilacqua stated that Bava wanted to create a stories about how terror can strike mankind in different time periods and asked his screenwriters to get him stories from books. After Bevilacqua finished his draft the screenplay, Marcello Fondato was brought in to work on it. Bevilacqua claimed that he was recalled for later rewrites, but that most of his added material was cut from the final film. American International Pictures approved of Bava's thematic idea but encouraged him to look for public domain titles. It was decided early in production that Boris Karloff would not only star in one of the tales, but also act as the film's host; he had recently hosted his own anthology television series, Thriller. Karloff was under contract with American International Pictures, and had just completed filming The Raven for them. The film's cinematographer is credited as Ubaldo Terzano, but Bava shot several scenes himself without credit. Filming Black Sabbath was made at the end of production of The Girl Who Knew Too Much during an eight-week period between February and March 1963. American International's involvement with the film allowed Salvatore Billitteri of Titra Sound Corporation to be on set to supervise the film for dubbing on its English-language release. As the film was going to be dubbed in different languages, actors could no longer phonetically pronounce their dialogue as it had to be done rhythmically to match various languages. Billitteri was also on set to give suggestions to Bava on how to make his film more appropriate for American audiences, which led to decreasing the amount of violence in the film. The film was first conceived under the title The Fear. Bava wanted to include a contemporary story which led to the development of "The Telephone". "The Telephone" has been described as one of Bava's first attempts at a giallo film. The giallo film is a style of Italian film that involves a murder mystery that emphasized stylish visuals, flamboyant music and violence. "The Telephone" was Bava's first color film that attempted to emulate the visual style of the covers that appeared on giallo digests. Some of the set pieces for "The Telephone" were taken from the black-and-white giallo film The Girl Who Knew Too Much (1962). "The Wurdulak" was the last of the short films to be shot,