[10] Initially released to Italian cinemas in 1979, then screened in America the following year, Caligula was met with legal issues and controversies over its violent and sexual content.

[11] Despite a generally negative reception, the film has gained notoriety as a cult classic[12] with significant merit for its political content and historical portrayal.

[13] A 178-minute Ultimate Cut, approved by McDowell and consisting entirely of new archival footage not used for the previous theatrical release, premiered at the Cannes Film Festival in 2023, receiving more favorable reviews from critics.

Tiberius enjoys swimming with naked youths and watching degrading sex shows that include deformed people and animals; Caligula observes with fascination and horror.

After Macro is executed in a gruesome public game, Caligula appoints Tiberius's former adviser Longinus as his personal assistant while pronouncing the docile Senator Chaerea as the new head of the Praetorian Guard.

Darker aspects of Caligula's personality emerge when he brutally rapes a virgin bride and her husband on their wedding day in a minor fit of jealousy and orders Gemellus's execution to provoke a reaction from Drusilla.

Initially unable to accept her death, Caligula has a nervous breakdown and rampages through the palace, destroying a statue of Isis while clutching Drusilla's body.

Now in a deep depression, Caligula walks the Roman streets disguised as a beggar; he causes a disturbance after watching an amateur performance mocking his relationship with Drusilla.

The new reign he leads becomes a series of humiliations against the foundations of Rome—senators' wives are forced to work in the service of the state as prostitutes, estates are confiscated, the old religion is desecrated, and the army is made to embark on a mock invasion of Britain.

[17] Vidal's script had a strong focus on homosexuality, leading Guccione to demand rewrites which toned down the gay content for wider audience appeal.

[15] Several mainstream actors were cast, Guccione intending to make a film that he felt, like Citizen Kane, would be a landmark in cinematic history.

[18] In The Encyclopedia of Epic Films, author Djoymi Baker describes Brass's screenplay as "an antiepic with an antihero, on a path of self-inflicted, antisocial descent".

[23] Guccione said this final draft was more violent than sexual, stating, "I maintain the film is actually anti-erotic ... in every one of its scenes you'll find a mixture of gore or violence or some other rather ugly things".

[22] Orson Welles was initially offered $1 million to star as Tiberius,[24] a figure which would have been his highest ever salary, but he refused on moral grounds when he read the script.

[25] Renowned actors who did accept roles in the film included Malcolm McDowell, Helen Mirren, Peter O'Toole and Sir John Gielgud, with Maria Schneider cast as Caligula's doomed sister Drusilla.

[19] Schneider became uncomfortable with appearing nude and in sexual scenes, and left the production, to be replaced by Teresa Ann Savoy, with whom Brass had previously worked on Salon Kitty.

[15] Brass decided not to focus much on Danilo Donati's elaborate sets, and intentionally kept the Penthouse Pets in the background during sex scenes, sometimes not filming them at all.

Guccione later said that Brass, apparently as a joke, would focus on "fat, ugly and wrinkled old women" and have them play the "sensual parts" intended for the Penthouse Pets.

Guccione and Lui "hired a skeleton crew, snuck back into the studios at night, raided the prop room"[15] and shot a number of hardcore sex scenes to be edited into the film.

[28][29] The new unsimulated sex scenes included Penthouse pets Anneka Di Lorenzo and Lori Wagner, who appeared as supporting characters in Brass's original footage.

[1][2] According to Kristopher Spencer, the score "is gloriously dramatic, capturing both the decadent atmosphere of ancient Rome and the twisted tragedy of its true story".

[41][42][43] In 1981, the Brazilian Board of Censors approved the establishment of special theaters to screen In the Realm of the Senses and Caligula because they were international box office hits.

[22] A Madison, Wisconsin, district attorney declined an anti-pornography crusader's request to prevent the release of Caligula on the basis that "the most offensive portions of the film are those explicitly depicting violent, and not sexual conduct, which is not in any way prohibited by the criminal law".

[22] The Penthouse attorney described the Fairlawn events as being driven by conservative morality reinforced by Ronald Reagan's presidential victory, stating: "Apparently, these extremists have interpreted a change by the administration to mean a clarion call for a mandate to shackle the public's mind again.

[57] Scott's review went on to say "Rome would seem to be at least as fecund a territory for the cinematic exploration of sex, death and money, as pre-war Japan ... but what's missing from Caligula, which is rife with all three, is any connective tissue (also any point of view, any thought, any meaning)".

The website's consensus reads: "Endlessly perverse and indulgent, Caligula throws in hardcore sex every time the plot threatens to get interesting.

[67] Positive criticism of the film came from Moviehole reviewer Clint Morris, who awarded it 3 stars out of 5, calling it "[a] classic in the coolest sense of the word".

[12] Helen Mirren has defended her involvement in the making of Caligula and even described the final product of the film as "an irresistible mix of art and genitals".

[38] In 2005, artist Francesco Vezzoli produced a fake trailer for an alleged remake called Gore Vidal's Caligula as a promotion for Versace's new line of accessories; the fake trailer featured Mirren as "the Empress Tiberius", Gerard Butler as Chaerea, Milla Jovovich as Drusilla, Courtney Love as Caligula and Karen Black as Agrippina the Elder, and an introduction by Gore Vidal.

[70] Producer Thomas Negovan announced a reconstruction of the film in 2020, seeking to follow Gore Vidal's original screenplay (rather than the visions of either Brass or Guccione).