While Edward Gibbons may quibble with the historical accuracy, Tinto Brass' epic is a full-blooded, visceral portrayal of the reign of Malcolm McDowell as Peter O' Toole murdering psychopath Caligula. The majority of the film can be seen, perhaps, as I, Claudius sans Christopher Biggins, but the insertion of several hardcore sex scenes post-production certainly add to the film's notoriety.
Looking beyond the myriad of fetishes on screen, such as lesbianism, troilism, masturbation and fellatio, the production values are surprisingly excellent, as would be expected from Fellini's production designer Danilo Donati, and the cast throw themselves into the film as only actors who have not read the entirety of the script can.
Brass himself disowned the film, despite it being little more than Salon Kitty with erections and money shots, which, in fact, are ably shot by Bob Guccione and Giancarlo Lui, and are seamlessly integrated into the film. Screenplay writer Gore Vidal would love to erase the film from the face of the earth, but any cineaste who would relish the sight of Alex the Droog fisting a bloke, or John Gielgud and Helen Mirren appearing in a hardcore porn film will, for the sake of the Senate, absolutely love this.