Since its theatrical release in 1973, The Exorcist, based on William Peter Blatty’s 1971 novel of the same name, has served as the cultural touchpoint for an otherwise mysterious religious ritual. In reality, it’s only part of the most recent chapter in the long history of the spiritual practice that involves far more than a spinning head and green projectile vomit.

“Exorcism is a prayer or ritual that is meant to remove the influence of demonic, evil power over a person,” says Stephen Okey, a theologian and assistant professor of philosophy, theology, and religion at Saint Leo University in Florida.

Many religious traditions believe that there are evil forces that can have a negative influence on a person's life and reports suggest that demand for exorcisms have increased since the turn of the century.

According to Okey, the term "exorcism" is most commonly associated with Christianity, especially Catholicism, partly because of the numerous explicit references to Jesus casting out spirits in the Gospels. In 2017, Pope Francis told priests that they “should not hesitate” to call on a Vatican-trained exorcist should they need one.

Below is a timeline highlighting episodes in the history of exorcism, beginning with its biblical roots.

The first four books of the New Testament of the Bible, known as the Gospels, tell the story of Jesus of Nazareth, a Jewish prophet whose life and teachings became the basis of Christianity. The first mention of Jesus casting away evil spirits appears in the Gospel of Mark, which is thought to have been written around A.D. 70, roughly 40 years after his death.

“In the New Testament, Jesus' exorcisms were evidence of his authority over the devil,” says Rob Haskell, ThM, a theologian specializing in the New Testament and former minister. “They showed that he had spiritual power.” In addition to describing exorcisms of humans, the Bible also includes at least one reference to animals being possessed by demons, he adds.

These biblical mentions serve as an introduction to the practice. “Since our understanding of exorcisms in the modern world comes from the Christian worldview, the New Testament sets the stage for all that follows,” Haskell explains.

Angry and disillusioned by the Catholic Church’s sale of indulgences—marketed to believers as a way to fast-track their way through repenting for their sins in purgatory—a German theologian named Martin Luther wrote a list of his complaints about the religion, which he may or may not have nailed to the door of his university’s church in 1517. His act of defiance sparked the split in Christianity known as the Protestant Reformation, and, in 1521, got him excommunicated from the Catholic Church by the pope himself.

Though Luther wasn’t the only reformer of the era, he was the most prolific, taking full advantage of the printing press and written word to spread his ideas on what Christianity should look like. This included publishing his Order of Baptism in 1523, followed by a 1526 revision that added exorcism to Protestant baptismal rites. In this situation, infant exorcism was done to help the baby reject the devil, sin and evil throughout their lifetime, rather than to cast out a demonic presence.

Not all Protestant denominations adopted the practice of exorcism, but for a period of time during the Renaissance, it was enough to make the question of how exorcisms should take place a controversial topic, says Katherine Walker, an assistant professor of English specializing in the history of magic at the University of Nevada, Las Vegas.

At that point, exorcism was well-trodden territory for Catholics, who had writings, teachings and rituals to guide them. Protestant exorcisms, on the other hand, were mostly conducted through prayer and fasting, and often involved entire communities, resulting in a public affair that could border on performance.

“In early modern England, we have many records of fantastic exorcisms conducted by clerics or sometimes by professional exorcists,” Walker explains. “Some of these latter were exposed as frauds.”

Along with these theatrical events, exorcisms became even more visible when writers like William Shakespeare began referencing them in their work (in his case, “King Lear” and “Twelfth Night”).

But amidst all this attention, skepticism arose as well. “Protestants increasingly viewed the entire rituals surrounding exorcism with hostility,” says Walker. And while that shift led to exorcism fizzling out among Protestants by the early 1600s, its presence in the period’s literature helped form its enduring cultural legacy.

Protestantism continued to spread throughout parts of Europe, eventually making its way to North America in the 17th century, by way of British colonists. Puritanism was the dominant Protestant denomination in America in the 17th and early 18th centuries, but changed over the course of a series of revivals known as “Great Awakenings” in the 1730s and 1740s, the 1790s, and from the late 1850s to the early 20th century.

The Baptist and Methodist denominations grew considerably as a result of these revivals, especially in the newly settled western parts of the country, as well as the south. Simultaneously, the 1800s also saw a rise in evangelicalism: an umbrella term applied to Protestant groups that believe in strict adherence to the Bible, being “born again,” the need to convert other people, and that the crucifixion of Jesus will lead to the salvation of humanity.

In the early 1900s, the Pentecostal movement emerged among American evangelicals. Pentecostalism focused on the Holy Spirit, and included supernatural components like glossolalia (better known as “speaking in tongues”), faith healing, miracles and exorcism.

While exorcisms had continued in the Catholic Church all along, they were not as prevalent in Protestant denominations throughout the 17th, 18th and 19th centuries. But Pentecostalism’s high-energy worship services and the lure of the possibility of receiving supernatural gifts from the Holy Spirit caused the movement to attract new members, and continue to grow throughout the first half of the 20th century.

Beginning in the 1950s, Evangelical Protestantism embarked on a period of rapid growth. Evangelists like Rev. Billy Graham took to the airwaves, gaining access to Americans’ homes through appearances on both radio and television, and became even more influential when he served as a spiritual advisor for President Dwight D. Eisenhower.

The following decade, increasing numbers of mainline Protestants (primarily Presbyterians and Episcopalians) and some Catholics began to adopt Pentecostal-style worship and a renewed focus on the Holy Spirit—a movement known as Charismatic Christianity. Like their Pentecostal counterparts, Charismatic Christians also performed exorcisms, sparking renewed interest in the ritual in the late 1960s and into the 1970s in the United States, as well as in Africa and Latin America.

It wasn’t long before exorcisms once again became embedded in popular culture, as they had during the Renaissance. William Peter Blatty’s 1971 novel The Exorcist—based on the real-life story of a 14-year-old boy who underwent Catholic exorcisms in Maryland and Missouri in 1949—kicked off the trend, reaching the top spot on the New York Times best-seller list, and remaining there for 17 weeks.

The film version of Blatty’s book was released in 1973, at a time Okey says was transitional both for cinema and for Catholicism. “The Exorcist had a huge influence on the rise of the horror genre, and films of the 1970s in general often had a grittier or rougher edge to them than films of the preceding decades,” he explains. “At the same time, the Catholic Church was working through the early effects of Vatican II and its effects on liturgy, relations with other religions and relations with the modern world.”