William Peter Blatty, author and screenwriter of “The Exorcist,” based his book on a real-life exorcism conducted on a boy, known as Roland Doe, who lived in this house in Prince George’s County. It is where his reported possession began in 1949. That winter, according to the boy’s parents and several books on the case, Roland’s bed began to shake violently, furniture moved across the room, and scratching noises were heard in the walls. After having Roland evaluated at Georgetown University Hospital, his parents met with the Rev. Albert Hughes, a Roman Catholic priest at St. James Parish, near their Maryland home. Hughes said he believed the boy was possessed and sought permission from the archbishop of Washington to begin the rite of exorcism.

William Peter Blatty, author and screenwriter of “The Exorcist,” based his book on a real-life exorcism conducted on a boy, known as Roland Doe, who lived in this house in Prince George’s County. It is where his reported possession began in 1949. That winter, according to the boy’s parents and several books on the case, Roland’s bed began to shake violently, furniture moved across the room, and scratching noises were heard in the walls. After having Roland evaluated at Georgetown University Hospital, his parents met with the Rev. Albert Hughes, a Roman Catholic priest at St. James Parish, near their Maryland home. Hughes said he believed the boy was possessed and sought permission from the archbishop of Washington to begin the rite of exorcism. Jim Lo Scalzo/European Pressphoto Agency

The film still captivates 40 years after its debut, in part because it draws on the real-life story of a Prince George’s County boy. Its screenwriter and author, William Peter Blatty, died yesterday.

Forty years after the movie’s debut, William Peter Blatty’s creation still captivates audiences, in part because it was based on a real-life story of a Prince George’s County boy.

Forty years after the movie’s debut, William Peter Blatty’s creation still captivates audiences, in part because it was based on a real-life story of a Prince George’s County boy.

The author of the thriller “The Exorcist” has new hope he has put the fear of God in Georgetown University.

William Peter Blatty, a Georgetown graduate, submitted to the Vatican last fall a petition with some 2,000 signatures calling for the school to be stripped of the labels Catholic and Jesuit. The petition said neither the faculty nor the student body was sufficiently Catholic, and Blatty complained about “scandals,” including that the school had invited then-Health and Human Services Secretary Kathleen Sebelius, a supporter of abortion rights, to speak.

What the Vatican plans to do was not immediately clear from its response, but it appeared somewhat encouraging to Blatty.

In a letter dated April 4, Archbishop Angelo Zani, secretary of the Vatican’s Congregation for Catholic Education, said the case could not be handled in the way Blatty had asked, because Blatty himself had not “suffered an objective change” at the hands of Georgetown.

However, the letter, first reported by the National Catholic Register, also said this: “Your communications to this Dicastery in the matter of Georgetown University . . . constitute a well-founded complaint,” Zani wrote. “Our Congregation is taking the issue seriously, and is cooperating with the Society of Jesus in this regard.”

A request for clarification from a Vatican spokesman was directed toward the Washington Archdiocese, which declined to comment.

Georgetown spokeswoman Stacy Kerr said the school has never received anything from the Vatican or the archdiocese, to which Blatty had also complained. Georgetown officials have disputed Blatty’s assertion that the university has lost its Catholic identity.

Chieko Noguchi, an archdiocese spokeswoman, declined to comment, saying Archbishop Donald Wuerl “has not been involved in the preparation of the petition nor the process undertaken to challenge the Catholic identity of Georgetown University.”

The effort was brought by Blatty and a group connected with the Cardinal Newman Society. The campaign represents the frustration of some conservative Catholics who want to see Catholic institutions more orthodox and uniform. They rally around Ex Corde Ecclesiae, a 1990 document by Pope John Paul II that gives instructions to colleges and universities about how to keep their Catholic identities.

Catholics have debated since 1990 what it means to satisfy Ex Corde and its guidelines on, for example, what percent of faculty members should be Catholic and what kind of credentials theologians at Catholic schools should have.

“Pope John Paul II was trying to say, ‘Here are common characteristics of what would be good to have at a Catholic college or university.’ Some people take that document and turn it into a checklist,” said Michael Galligan-Stierle, president of the Association of Catholic Colleges and Universities. “It falls to the bishop at the end of the day to read that document” and consider all the specifics of a school, such as its setting and its work, he said.

Asked how a Catholic school could satisfy Ex Corde if it hosts people and conversations supporting abortion rights, for example, Galligan-Stierle said: “It’s very important our colleges prepare students to engage culture in a substantive way. . . . That’s different than advancing a certain method.”

In addition to writing the novel “The Exorcist,” Blatty produced and wrote the screenplay for the movie, which is one of the top-grossing R-rated films in history. It is about the demonic possession of a girl, a troubled Georgetown University priest who is assigned to her case and the Prospect Street NW home where the nightmare unfolds.