Demonstrating prodigious strength, speaking in an unknown language, and exhibiting other allegedly diabolical feats supposedly characterize the “true story” behind The Exorcist. The 1973 horror movie-starring Linda Blair as the devil-plagued victim-was based on the 1971 bestselling novel of that title by William Peter Blatty. The movie, reports one writer, “somehow reached deep into the subconscious and stirred up nameless fears.” Some moviegoers vomited or fainted, while others left trembling, and there were “so many outbreaks of hysteria that, at some theaters, nurses and ambulances were on call.” Indeed, “Many sought therapy to rid themselves of fears they could not explain. Psychiatrists were writing about cases of 'cinematic neurosis'” (Allen 2000, viii-ix).
Blatty had heard about the exorcism performed in 1949 and, almost two decades later, had written to the exorcist to inquire about it. However the priest, Father William S. Bowdern, declined to assist Blatty because he had been directed by the archbishop to keep it secret. He did tell Blatty-then a student at Washington’s Georgetown University, a Jesuit institution-about the diary an assisting priest had kept of the disturbing events (Allen 2000, ix-x).
The diary-written by Father Raymond J. Bishop-consisted of an original 26-page, single-spaced typescript and three carbon copies, one of which was eventually provided to Thomas B. Allen, author of Possessed, and included as an appendix to the 2000 edition of the book. The copy came from Father Walter Halloran, who had also assisted with the exorcism. Halloran verified the authenticity of the diary and stated that it had been read and approved by Bowdern (Allen 2000, 243, 301).
The diary opens with a “Background of the Case.” The boy, an only child identified as “R,” was born in 1935 and raised an Evangelical Lutheran like his mother; his father was baptized a Catholic but had had “no instruction or practice” in the faith. The family’s Cottage City, Maryland, home included the maternal grandmother who had been a “practicing Catholic until the age of fourteen years” (Bishop 1949, 245).
On January 15, 1949, R and his grandmother heard odd “dripping” and scratching noises in her bedroom, where a picture of Jesus shook “as if the wall back of it had been bumped.” The effects lasted ten days but were attributed to a rodent. Then R began to say he could hear the scratching when others could not. Soon a noise as of “squeaking shoes"-or, one wonders, could it have been bedsprings?-became audible and “was heard only at night when the boy went to bed.” On the sixth evening the scratching noise resumed, and R’s mother and grandmother lay with him on his bed, whereupon they “heard something coming toward them similar to the rhythm of marching feet and the beat of drums.” The sound seemed to “travel the length of the mattress and back again” repeatedly (Bishop 1949, 246). Was R tapping his toes against the bed’s footboard?
https://www.csicop.org/si/show/exorcism_driving_out_the_nonsense