Trivia

Peter O'Toole and John Gielgud claimed to have been unaware hardcore sex footage was being shot for the film.

Prior to his hiring of Tinto Brass to direct, Bob Guccione had been in negotiations with John Huston, and then Lina Wertmüller - who wanted to cast Jack Nicholson in the film's starring role.

The full-scale Roman vessel, complete with 120 hand-carved oars, was the largest prop ever built at that time; it was over 175 feet long and 30 feet high.

A Yugoslavian stallion named Davide was cast as Caligula's horse, Incitatus.

It is believed that over 2,500 people took part in the making of the movie, including actors, extras, carpenters, artisans, caterers.

At least two sequences were created completely in the editing room:

• In the original conception, three men were seen talking and bathing in red mud. They are startled when Caligula first appears in the hallway outside Tiberius's pool. As Caligula walks down the hall, we see fragments of tortures that occur on the other side of the curtain. In the movie, the scene with the three men was moved *after* Nerva's death, and entirely new dialogue was dubbed over the shot, making it appear that the men are discussing Nerva's recent death and Tiberius's imminent death. They appear to be startled, then there is a cut to Caligula across the palace, fantasizing about torture, intercut with the fragments of tortures that were meant to be about 15 minutes earlier in the film.
• Unused bits from the scene where Chaerea, Longinus, and a few senators discuss the possibility of Caligula dying from a fever were used to build a new scene toward the end of the film where (it appears) the men plot Caligula's murder. Almost all of the dialogue in this scene was invented in the dubbing stages, and most shots obscure the mouths of each speaker.

Several different versions of the film have been circulated: - Caligula was originally released in the UK with a running time of 149 minutes, with the hardcore sex replaced by alternate footage inserted by the distributor. However, the latest UK release (and now legal version) has a PAL running time of 98 minutes, 34 seconds (approximately 102 minutes film/NTSC), and is the same as the older R-rated version in the USA. The original 149 minute cut is now highly sought-after. - A 105 minute R-rated version was released in the USA in 1981. This version also used alternate footage and angles in the hardcore sex scenes and during scenes of graphic violence. - The official "uncut" version runs at 156 minutes and includes about six minutes of re-shoots by Bob Guccione. - In 1984, the film was re-cut and re-released in Italy under the title Io, Caligola. It ran 133 minutes, and was cut to 123 minutes by the Italian censors. When released on home video, some of the hardcore footage shot by Bob Guccione were reinserted into the film. - The second (and current) R-rated version was released in 1999 and used no alternate footage or angles, with the same shots repeating several times to mask the cuts in the film. The rumors of a 210-minute version screened at the Cannes Film Festival in 1979 are untrue - see note below.

Although he later sued to have his name removed from the credits, Gore Vidal received $225,000 for his work on the screenplay.

John Gielgud was originally offered the role of Tiberius, but declined: he only accepted the smaller part of Nerva after being sent a letter by Gore Vidal.

After the film was released, Anneka Di Lorenzo (aka Marjorie Lee Thoresen, a 1975 Penthouse Pet of the Year), who played Messalina, sued Bob Guccione, saying that his handling of the film, mainly his adding of the hardcore sex inserts, had damaged her acting career by associating her with a hardcore porno film. She won her case, but was awarded only $4.06 in damages.

Gore Vidal had originally scripted the role of Drusilla (at least in the very early drafts of the screenplay) for his close friend, Claire Bloom.

The film's screenplay was developed from an unproduced television mini-series treatment, written by Roberto Rossellini.

Despite popular beliefs, Gore Vidal and Tinto Brass did not disown this film because Bob Guccione inserted hardcore sex and graphic violence sequences and changed the point of the film. In reality, only five or six minutes of the 156-minute version of the film was part of Guccione's reshoot - that five or six minutes consists of the lesbian tryst in the secret room, and several inserts in the imperial bordello scene. Everything else was shot by Brass. Vidal disowned the film because Brass and lead actor Malcolm McDowell changed the point of view of his screenplay. Brass disowned it because Guccione locked him out of the editing room (some in the industry suspect it was because Brass didn't want to use Guccione's hardcore inserts) after assembling the first 40 minutes (which was probably disassembled shortly afterward). Guccione then proceeded to edit the film himself, but he often chose shots that were never meant to be included (the many zooms, out-of-focus shots, etc.), and also cut up certain scenes and put them in the wrong order. A prime example of this is Caligula's nightmare scene with Drusilla, which now occurs in a part of the film that would have been quite impossible dramatically, and is actually the first half of an earlier scene, which occurs just after the credits (together, the two scenes were meant to be the opening of the film, and the current opening in which Caligula and Drusilla enjoy a romp through a forest was intended for an entirely different purpose altogether, and was meant to occur much later).

Charlotte Rampling said in an interview that she was also offered a part.

Malcolm McDowell claims to have talked Katharine Ross out of taking the role of Drusilla.

According to a Tinto Brass interview both Maria Schneider and Isabelle Adjani tested for the role of Drusilla. Schneider won the role but left the production after a few days filming, due to an argument over the amount of nudity revealed in her costume during Tiberius's funeral scene.

The film was banned in Russia until 1993.

A whopping $7.50 was the first-run admission price at its US premiere, at the Penthouse East Theatre, New York City in 1980. Average prices of movie tickets back then were around $3.

One of the few movies legendary film critic Roger Ebert admitted to walking out on (during the Brothel-Boat orgy sequence), calling it "sickening, utterly worthless, shameful trash. If it is not the worst film I have ever seen, that makes it all the more shameful: People with talent allowed themselves to participate in this travesty." He reviewed what he saw, giving it zero stars, and ended with a quote from another viewer who told him "This movie is the worst piece of shit I have ever seen."

Contrary to the popular beliefs, the infamous 210 minute pre-release version of the film never existed. The mix-up came from an erroneous film program printed for the first public screen of "Caligula" at the Cannes Trade Festival (not to be confused with the Cannes Film Festival that occurs around the same time of the year) that stated that the entirety of the "Caligula Screening" runs 210 minutes. What it forgot to say, however, was that both the film (in its 156 minute edition) and the one hour making-of featurette were shown back to back that night, thus creating the three and a half hour running time.

Helen Mirren and John Gielgud star alongside one another in this movie. They have portrayed the same character, Hobson, in a Arthur related project: Gielgud played the character in "Arthur", for which he won an Oscar and had a cameo in its sequel "Arthur 2: On the Rocks", while Mirren played Hobson in the 2011 remake.