Caligula (Italian: Caligola) is a 1979 Italian-American erotic historical drama film focusing on the rise and fall of the Roman Emperor Caligula. It stars Malcolm McDowell, Teresa Ann Savoy, Helen Mirren, Peter O'Toole, John Steiner and John Gielgud. It is the only feature film produced by the men's magazine Penthouse. Producer Bob Guccione, the magazine's founder, intended to produce an explicit pornographic film with a feature film narrative and high production values. He also cast Penthouse Pets as extras in unsimulated sex scenes filmed during post-production by himself and Giancarlo Lui.
Guccione hired screenwriter Gore Vidal to draft the film's script and Tinto Brass to direct the film. Brass extensively altered Vidal's original screenplay, leading Vidal to disavow the film. The final screenplay focuses on the idea that "absolute power corrupts absolutely". Brass and Guccione disagreed over Guccione's use of unsimulated sexual content, which Brass refused to film. Because the producers did not allow Brass to edit the film, they changed its tone and style significantly and added hardcore sex scenes not filmed by Brass, thus turning Caligula into a pornographic drama that disregarded the director's intentions to present the film as a political satire. As a result, Brass also disavowed the film.
Caligula's release was controversial; it was met with legal issues and controversies over its violent and sexual content. Its uncut form remains banned in several countries. Although reviews were overwhelmingly negative (though McDowell's performance as the title character was praised), Caligula is considered to be a cult classic and its political content was considered to have significant merit.
The script was later adapted into a novelization written by William Johnston, working under the pseudonym William Howard.