Filming
Produced for $7 million, it was the most expensive film ever made at the time. It became MGM's largest grosser since Gone with the Wind (1939). Filmed at the sprawling Cinecitta Studios that had been opened by Benito Mussolini in 1937 as part of the dictator's master plan to make Rome the pre-eminent world capital. (Mussolini's son Vittorio Mussolini and Hollywood producer Hal Roach negotiated to form the R.A.M. ["Roach and Mussolini"] Corporation later in 1937, which was ultimately aborted. This business alliance with the Fascist state horrified 1930s Hollywood moguls and ultimately led to Roach defecting from his MGM distribution deal to United Artists in 1938.)
Filming in postwar Italy offered American studios immense facilities and cheap Italian labor and extras, of which thousands were required. Hollywood returned to Cinecitta often, producing many of its biggest spectacles there, including Helen of Troy (1956), Ben-Hur (1959), and Cleopatra (1963), with the latter two dwarfing Quo Vadis in scale. The studio would later be used by many Italian producers and directors, including Federico Fellini. The first use of the phrase "Hollywood on the Tiber", which has come to refer to a golden era of American runaway film production in Italy, was as the title of a Time article in the issue dated June 26, 1950, published while Quo Vadis was being shot in Rome.
Composer Miklós Rózsa said that he wrote most of his score at the Culver City studios while the film was being shot in Italy:
[The] rushes were being sent back to Hollywood for cutting at the same time as they were being cut back in Rome ... I set to work so that at least something was ready, even if it had to be modified later. I worked with the chief supervising editor, Margaret Booth, whose technical knowledge is incomparable ... Finally, the Rome contingent arrived home with their version. It wasn't so very different from the one that Margaret had put together, and there were no insuperable problems. Sam Zimbalist was amazed and delighted that I had all the music ready in three weeks, thanks to the work Margaret and I had already done.
Ten Italian locations were used in the film. With the exception of the Via Appia, most of these have not been identified, but the final stage of the chariot chase was filmed along the 2000-year-old Viale dei Cipressi (Avenue of Cypresses) near the village Bolgheri. This landmark in Livorno Province, Tuscany, is easily recognizable.
In the summer of 1950, when Quo Vadis was in production, Rome was in the grip of an intense heatwave, as Peter Ustinov recalled: "Rome was in the throes of Holy Year, and bursting with pilgrims. It was also one of the hottest summers on record." The heat affected not only the cast and crew, but also the lions. Mervyn LeRoy recalled that because of the heat, the lions were reluctant to enter the arena.
Due to equipment shortages in Italy, MGM had to import a reported two hundred tons of generators, lights and other electrical equipment from Culver City.
The film holds the record for the most costumes used in one movie: 32,000.
At one point in the film, Nero shows his court a scale model illustrating his plans for the rebuilding of Rome as a new city to be called Neropolis. Studio publicity claimed that this was the model of Ancient Rome housed in the Museum of Roman Civilization and that it had been borrowed from the Italian government. (This was originally constructed by Mussolini's government for a 1937 exhibition of Roman architecture.) However, the museum model is of fourth-century Rome, not of first-century Rome as it would have looked when rebuilt after the Great Fire of AD 64. The screen model looks nothing like the museum model. (It was almost certainly constructed especially for the film – perhaps by its special effects model-maker, Donald Jahraus.)
Anthony Mann worked on the film as an uncredited second-unit director. He spent 24 nights (four working weeks) on the Cinecitta backlot shooting scenes for the Burning of Rome sequence. However, he was not the co-director of the film, as some of his admirers have claimed. The soundstage scenes for the same sequence were directed by Mervyn LeRoy.