Born in Modena, Italy in 1925, the real Amorth became a Roman Catholic priest in 1954. Just over thirty years later, he was appointed an exorcist of the Diocese of Rome, and after four years in the role he founded the International Association of Exorcists, where he remained president until he retired in 2000.

“From the age of 15 I knew [the church] was my true vocation,” Amorth said. “I knew nothing of exorcism — I had given it no thought — until June 6, 1986 when Cardinal Poletti, the then Vicar of Rome, asked to see me. There was a famous exorcist in Rome then, the only one, Father Candido, but he was not well, and Cardinal Poletti told me I was to be his assistant. I learnt everything from Father Candido. He was my great master. Quickly I realised how much work there was to be done and how few exorcists there were to do it. From that day, I dropped everything and dedicated myself entirely to exorcism.”

At one point, Father Amorth claimed to have performed 160,000 exorcisms over the course of his ministry, a number that was largely questioned. Amorth addressed this considerable tally by explaining that some exorcisms took minutes, while some took place over several hours, hinting that each single prayer could count as an exorcism, and saying that some people require hundreds of exorcisms and are possessed by many demons.

The church first tackles exorcisms by taking into account whether they’re major or minor cases, and only after a complete medical and psychiatric examination has been completed. A minor exorcism may include prayers or invocations delivered by a priest and any other people who have gathered to join in, but when it is thought that demonic possession is involved, the Psalms and Gospels may be read, along with exorcistic prayers. As in the movies, holy water, crucifixes and the sign of the cross may be used in when performing the rituals.

“Satan is pure spirit,” Amorth said. “He often appears as something else, to mislead. He appeared to Padre Pio as Jesus, to frighten him. He sometimes appears as a raging animal. The ritual of exorcism is not practiced by an ordinary priest. An exorcist requires specific training and must be thought to have a personal sanctity. He can be exposed to dangerous behavior and personal threat. His prayers often cause a violent response as he attempts to shine a beam of light into the darkness.”

After Exorcist director Friedkin finally met Amorth – describing him as having a “razor-sharp” mind and a jovial manner – he released the 2017 documentary The Devil and Father Amorth, which featured footage of the ninth exorcism of an Italian woman in the village of Alatri, as performed by Amorth.