The title was changed to The Miracle of Fatima to fit on marquees, according to an undated DV news item found in the production files at the AMPAS Library. After the opening credits, a montage with voice-over narration describes how a socialist minority proclaimed a "Peoples' Republic," which sought to destroy the power of the Church through the uprising of a police state in Portugal. The first name of actress Frances Morris was mistakenly spelled "Francis" in the onscreen credits. Actress Nanette Fabares, who played "Florinda" in the film, subsequently changed her name to Nanette Fabray. According to a Feb 1952 HR news item, radio actor Steve Roberts was cast, under a different name, but that name has not been determined. Juvenile actress Susan Whitney portrayed "Lucia" both as a child and as a forty-year-old nun.
       The true story of the events at Fatima began in 1916 when a nine-year-old Portuguese girl, Lucia Dos Santos, and her cousins Francisco and Jacinta Martos, aged eight and six respectively, reported seeing a vision of a male angel who called himself "the Angel of Peace." According to the children, the angel, who appeared to them while they tended their parents' sheep, appeared again a year later. When he vanished, the form of a beautiful Lady appeared, who promised to appear at the same time each month until October. During her appearances, the Lady reportedly predicted the deaths of Francisco and Jacinta, the end of World War I and the subjugation of religion in Russia. In Jul 1917, the children related that the Lady told them what is now called the "Secret" or the "Three Secrets," as it consisted of three parts; the secrets were not disclosed to the public for many years.
       As depicted in the film, the children were kidnapped and held for two days in Aug 1917 by civil authorities, who threatened and interrogated them. The Lady then appeared to the children on 19 Aug and promised a great miracle in October. The miracle on 13 Oct 1917 was witnessed by thousands of pilgrims who described how the sun seemed to fall from the sky twice and bathe the area in colored lights, healing many of the sick and disabled, and leaving the earth dry, in spite of an earlier rain. Witnesses included a skeptical Lisbon journalist, whose reports in O Seculo, changed from mocking to astonishment after the event. By 1920, both Marto children had died, and later, Lucia became a Carmelite nun.
       In 1941, Lucia wrote memoirs in which two of the three parts of the "Secret" were revealed. The first part was a vision of hell and a plea to pray and sacrifice to save souls. The second part prophesied the beginning of World War II and called for the consecration of Russia. The last part, which Lucia later wrote down and which had been kept in a sealed envelope by Pope Pius XII, was to be unveiled in 1960. Pope John XXIII read it in 1960, resealed it and, although every successive pope read it, according to a Dec 1999 LAT article, it remained secret from the public. Although many followers speculated that the third part was a prediction of either a major spiritual crisis in the Catholic Church or, as the twentieth century came to a close, of an apocalypse, the LAT article reported that Cardinal Joseph Ratzinger, who read the secret, claimed that no apocalyptic events were predicted. At that time, Monsignor Francis Maniscalco, a spokesman for the Bishops Conference held in Washington, D.C, announced that Pope John Paul II had no plans to release the "Secret."
       According to a May 2000 LAT article, John Paul finally unveiled the remaining secret, announcing that it was a "prophetic vision" of Christian suffering and martyrdom in the twentieth century and that among the many events the "Secret" foretold was a 13 May 1981 assassination attempt on his life, which occurred exactly sixty-four years after the first reported sighting of the Lady on what became the feast day of Our Lady of Fatima. Some followers were skeptical, however, as many of the predictions of the "Secret" have been revealed only after the events occurred. As of 2003, Francisco and Jacinta had been beatified, the first pre-adolescent candidates who did not die as martyrs. Lucia, a cloistered Carmelite nun in Portugal, was not eligible for beatification at that time, as it is only bestowed on the dead. She died on 13 Feb 2005 at the age of 97.
       Two fictitious characters in The Miracle of Our Lady of Fatima, "Ferreira" and "DaSilva" may have been named to honor Bishop DaSilva, the Bishop of Leiria/Fatima, who ordered Lucia to write down the third part of the "Secret," and Bishop Ferreira, Archbishop of Gurza, whom Lucia entrusted with the sealed envelope containing the "Secret." According to a Jan 1952 HR news item, the film was rushed into production after two foreign-made pictures on the same subject were exhibited in the U.S. According to several contemporary sources, much of the film was shot in Portugal, and the Var review reported that footage was used of the 13 Oct 1951 Fatima celebration, when Fatima was the site of the solemn closing of the Holy Year. In a HR news item, Bryan Foy stated that the cost of the film was $1,400,000, and the same source states that this was the first film to use the WarnerColor process. However, two films, The Lion and the Horse and Carson City, began production using WarnerColor in mid-1951, several months prior to The Miracle of Our Lady of Fatima, and were the first two WarnerColor films to be released.
       According to a Nov 1952 Var news item, the Allied Independent Theatre Owners of Iowa and Nebraska complained that the high terms demanded by Warner Bros. made it impossible for members to show the film, claims which Warner Bros. denied. Max Steiner was nominated for an Academy Award for Best Scoring of a Dramatic or Comedy Picture for this film, but lost to Dimitri Tiomkin for High Noon. According to a Jul 1952 LADN news item, the film won a special award from the Los Angeles Electrical Engineers Association for its unusual lighting effects. It also received the National Screen Council's Blue Ribbon Award for Oct 1952, according to a Nov 1952 Box article. In a Dec 1952 HR news item, the film was announced as the outstanding picture of the year by the national Catholic monthly, The Sign, and a Sep 1952 MPH news item reported that it won the Christopher Award. The Miracle of Our Lady of Fatima marked the film debut of fifteen-year-old Albert Walters. Susan Whitney, Sammy Ogg and Jay Novello reprised their roles in a Lux Radio Theatre broadcast called The Miracle of Fatima on 30 Mar 1953. J. Carrol Naish played "Hugo" and Jeanette Nolan played "Rosa Maria." Several films have been made in Portugal about the vision at Fatima, including the 1951 La Señora de Fátima, directed by Rafael Gil.