After filming, Gregory Peck informed the producers that, as Audrey Hepburn was certainly going to win an Oscar (for this, her first major role), they had better put her name above the title. They did and she did.
Director William Wyler normally films a lot of takes getting the movie right. But The Mouth of Truth scene only took one take. Not known to Audrey Hepburn, Gregory Peck hid his hand in his sleeve when he took it out of the Mouth. Hepburn's reaction therefore is both genuine and spontaneous: exactly what Wyler was looking for.
A lot of the film's success was attributed to the public's then fascination with Britain's Princess Margaret who was creating a stir over her much publicized relationship with commoner Peter Townsend. (The Princess was forced to renounce her true love because he was divorced and marry more "suitably".)
Audrey Hepburn won the 1953 Best Actress Academy Award for Roman Holiday (1953). On March 25th, 1954, she accepted the award from the much revered Academy president Jean Hersholt. After accepting the award, Audrey kissed him smack on the mouth, instead of the cheek, in her excitement. Minutes after accepting her 1953 Oscar, Audrey realized that she'd misplaced it. Turning quickly on the steps of the Center Theater in New York, she raced back to the ladies' room, retrieved the award, and was ready to pose for photographs.
When Gregory Peck came to Italy to shoot the movie, he was privately depressed about his recent separation and imminent divorce from his first wife, Greta Kukkonen. However, during the shot he met and fell in love with a French woman named Veronique Peck. After his divorce, he married Passani and they remained together for the rest of his life.
Audrey Hepburn won the role of Ann thanks to a legendary screen test. In it, she performed one of the scenes from the film, but the cameraman was instructed to keep the cameras rolling after the director said, "Cut." Several minutes of unrehearsed, spontaneous Hepburn was thus captured on film and this, combined with some candid interview footage, won her the role.
The original writer, Dalton Trumbo, was blacklisted as one of the legendary Hollywood Ten, and therefore could not receive credit for the screenplay, even when it won the Academy Award for Best Motion Picture Story. Instead, his friend, Ian McLellan Hunter, one of the writers of the final screenplay, took credit for the original story and accepted the Oscar. Trumbo's wife, Cleo, was finally presented with the award in 1993, long after his death in 1976. The Oscar she received was actually a second one, because Hunter's son wouldn't give up his father's Oscar. Thus, two awards for Best Motion Picture Story of 1953 exist. The story credit was corrected to credit Trumbo when the restored edition was released in 2002, nearly fifty years after the original release.
Gregory Peck's role was originally written with Cary Grant in mind. Grant, however, turned the role down as he believed he was too old to play Audrey Hepburn's love interest. He did, however, play her on-screen love ten years later in Charade (1963). The two became firm friends working on the film, and Grant considered her one of his favorite actresses to work with.
Paramount originally wanted to shoot this movie in Hollywood. William Wyler refused, insisting it must be shot on location. They finally agreed, but with a much lower budget. This meant the movie would now be in Black-n-White, not the expected Technicolor, and he would need to cast an unknown actress as the Princess - Audrey Hepburn.
By the time he got the script for this film, Gregory Peck was hungry to do a comedy (he had not been in a comedy on film) and jumped at this opportunity. He later said that, at the time, he felt like every romantic comedy script he had the chance to read "had the fingerprints of Cary Grant on it".
At the end of production, Paramount Studios presented Audrey Hepburn with her entire wardrobe from the film, including hats, shoes, handbags, and jewelry. These gifts were intended as wedding presents; however, soon after production, Hepburn ended her engagement to James (later Lord) Hanson, a businessman.
The story was originally optioned by Frank Capra in 1949, who had hoped to cast Cary Grant and Elizabeth Taylor in what would essentially amount to being a variation on his Oscar-winning classic, It Happened One Night (1934). However, Capra's Liberty Films production company was beset with financial problems and he was forced to sell the property to Paramount where a combination of political timidity (Capra discovered the involvement of blacklisted writer Dalton Trumbo) and a tight budget prompted him to withdraw from the project. William Wyler, however, had no compunctions whatsoever about working with Trumbo.
The airplane in which the Secret Service men arrive to search for Princess Ann is a very unusual type, the Breda-Zappata BZ.308, of which only one prototype was built in 1949 (for the Italian Air Force). It was scrapped shortly after its appearance in the movie.
The Roman summer was stiflingly hot, with the temperatures in the high 90s. Crowds swarmed over all the locations, making huge impromptu audiences for the actors. Meanwhile, Italy itself was beset with clashes between political parties that resulted in strikes and unrest that threatened to disrupt production.
First choices for the part of the princess were Jean Simmons and Suzanne Cloutier. Elizabeth Taylor was also considered for the part. Both Taylor and Simmons had to be immediately ruled out as they were preoccupied with other projects at the time.
Ann and Joe get into an argument over which poet wrote the words that Ann quotes, "Arethusa rose from her couch of snows in the Acroceraunian mountains." Joe was right; it's from the poem "Arethusa" by Percy Bysshe Shelley.
Audrey Hepburn was performing on Broadway in "Ondine" with her future husband Mel Ferrer when she won best actress for "Roman Holiday." Later that year, she won the Tony for her performance in "Ondine," making her one of only two actresses to win the Oscar and the Tony in the same year. Ellen Burstyn is the other, winning the Oscar for "Alice doesn't live here anymore," and the Tony for "Same time, next year."
When Joe (Gregory Peck) is putting Princess Ann (Audrey Hepburn) in the cab, she says "It's a taxi!" and he says "It's not the Super Chief!" Joe was referring to a train and route of the Atchison, Topeka and Santa Fe Railroad. In the 1940s and 1950s, ATSF marketed it as "The Train of the Stars" because it supposedly carried celebrities on every passage between Chicago, Illinois, and Los Angeles, California. The SC was the first Diesel powered, full Pullman sleeping car train in the USA, setting the standard for American luxury train travel. Initially, with one set of equipment, it ran once in each direction each week between Chicago and Los Angeles. Later, after taking delivery or more engines and coaches, it ran twice in each direction each week, and finally daily after 1948.
George Stevens was the next director to inherit the project after Frank Capra bailed, but Stevens declined to pursue it. The property was then offered to William Wyler, who was coming off the back of two very weighty dramatic movies - The Heiress (1949) and Detective Story (1951) - and was only too glad to tackle a light romantic comedy, his first since the mid 1930s. Wyler was also very keen to work abroad in order to exploit a tax loophole.
One of the reasons why William Wyler was anxious to film in Europe was because he wanted to put some distance between himself and the House Un-American Activities Committee, which was threatening to embroil him in their investigations because of his liberal stance.
The trivia items below may give away important plot points.
For the famous "Mouth of Truth" scene, Gregory Peck ad-libbed the joke where he pretends that his hand was bitten off in the mouth of the stone carving. He borrowed the gag from Red Skelton. Prior to filming the scene, Peck told director William Wyler that he was going to do the gag, but that they should not tell Audrey Hepburn. When Peck pulled his arm out of the stone carving's mouth with his hand pulled up his sleeve, Hepburn's horror and surprise was genuine. She gave what she later recalled was "a good and proper scream," and the scene was finished in one take.
When filming the scene where the princess (Audrey Hepburn) says her goodbyes to Joe, the inexperienced Hepburn was unable to produce the necessary tears, eventually causing director William Wyler to complain at the number of wasted takes. Hepburn promptly burst into tears and the scene was filmed successfully.