Due to death threats against Linda Blair from religious zealots who believed the film "glorified Satan", Warner Bros. had bodyguards protecting her for six months after the film's release.

In an interview, Jason Miller stated that he had a major verbal confrontation with William Friedkin after the director fired a gun near his ear to get an authentic reaction from him. He told Friedkin that he is an actor, and that he didn't need a gun to act surprised or startled.

The scene where Regan projectile vomits at Father Karras only required one take. The vomit was intended to hit Jason Miller in the chest, but the plastic tubing misfired, hitting him in the face. His reaction of shock and disgust while wiping away the vomit is genuine, and Miller admitted in an interview that he was very angered by this mistake.

On the first day of filming the exorcism sequence, Linda Blair's delivery of her foul-mouthed dialogue so disturbed the gentlemanly Max von Sydow that he actually forgot his lines.

The Exorcist is the first horror film to be nominated for the Academy Award for Best Picture. The only other one is Kao ära (2017). Lõuad (1975), Voonakeste vaikimine (1991) and Kuues meel (1999) were all nominated, and "The Silence of the Lambs" won, but, these films are not designated as horror films on IMDB.

This is Warner Brothers' highest grossing film of all time when adjusted for inflation.

Actress Mercedes McCambridge, who provided the voice of the demon, insisted on swallowing raw eggs and chain smoking to alter her vocalizations. Furthermore, the actress who had problems with alcohol abuse in the past, wanted to drink whiskey as she knew alcohol would distort her voice even more, and create the crazed state of mind of the character. As she was giving up sobriety, she insisted that her priest be present to counsel her during the recording process. At William Friedkin's direction, McCambridge was also bound to a chair with pieces of a torn sheet at her neck, arms, wrists, legs and feet to get a more realistic sound of the demon struggling against its restraints. McCambridge later recalled the experience as one of horrific rage, while Friedkin admitted that her performance--as well as the extremes which the actress put herself through to gain authenticity--terrifies the director to this day.

Father Dyer is played by William O'Malley, an actual priest who until 2012 taught at Fordham Prep, a Jesuit high school.

Linda Blair received her Best Supporting Actress Oscar nomination before it was widely known that previous Supporting Actress winner Mercedes McCambridge had actually provided the voice of the demon. By Academy rules once Blair was given the nomination it could not be withdrawn, but the controversy about Blair being given credit for another actress' work ruined her chances of winning the award.

Upon its initial theatrical release the film affected many audiences so strongly that at many theaters, paramedics were called to treat people who fainted and others who went into hysterics.

The bedroom set had to be refrigerated to capture the authentic icy breath of the actors in the exorcising scenes. Linda Blair, who was only in a flimsy nightgown, says to this day she cannot stand being cold.

If adjusted for inflation, this would be the top grossing R-rated film of all time.

The original teaser trailer, which consisted of nothing but images of the white-faced demon quickly flashing in and out of darkness, was banned in many theaters, as it was deemed "too frightening".

Jack Nicholson was up for the part of Father Karras, before Jason Miller landed the role. William Friedkin thought he was too unholy to ever play a priest.

Mercedes McCambridge had to sue Warner Brothers for credit as the voice of the demon. William Friedkin, on the Diane Riehm Show (NPR, 29 April 2012) said that originally she didn't want a credit, saying that she wanted the audience to believe the voice was Regan's. However, after it was released she changed her mind, and was given the credit.

According to William Friedkin, the subliminal shots of the white faced demon are actually rejected makeup tests for Regan's possessed appearance.

The contortionist Linda R. Hager was hired to perform the famous "spider walk" scene, which was filmed on April 11, 1973. Ms. Hager was able to perform the scene by use of a harness and flying wires hung above the staircase used in the set; she would advise Friedkin when she was just barely touching the stairs with her hands and feet; and then she maintained that light touch as she was moved down the staircase by the harness and wires. William Friedkin deleted the scene before the film's December release. He felt it was "too much" of an effect because it appeared so early in the film. He later admitted that another reason for omitting the scene was that there was no way to hide the wires from view at the time. Almost 30 years later, Friedkin changed his mind and added the scene back for the extended 2000 version, with the wires digitally removed.

The film received an 18 certification in Israel and was shown in Lebanon but banned in the rest of the Middle East. Lebanon banned the film when it was re-released.

Author William Peter Blatty once won $10,000 on the Groucho Marx show You Bet Your Life (1950). When Groucho asked what he planned to do with the money, he said he planned to take some time off to "work on a novel." This was the result. Groucho is mentioned in the film by Lt. Kinderman in jest as playing Othello.

One of the most famous scenes in the movie and the shot used for the posters and the cover of the DVD/VHS releases was inspired by the 1953-1954 series of paintings "Empire of Light" ("L'Empire des lumières") by René Magritte. It is the scene where Fr. Merrin steps out of a cab and stands in front of the MacNeil residence bathed in an eerie glow.

Director William Friedkin eventually asked technical advisor Thomas Bermingham to exorcise the set. He refused, saying an exorcism might increase anxiety. Rev. Bermingham wound up visiting the set and gave a blessing and talk to reassure the cast and crew.

Ellen Burstyn agreed to doing the movie only if her character didn't have to say the scripted line: "I believe in the devil!" The producers agreed to eliminate the utterance.

When originally released in the UK a number of town councils imposed a complete ban on the showing of the film. This led to the bizarre spectacle of "Exorcist Bus Trips" where enterprising travel companies organised buses to take groups to the nearest town where the film was showing.

In the documentary included on the 25th Anniversary Edition, the actors reveal that in many shots it was not necessary to "act", as what was captured on film were genuine reactions. For example, Ellen Burstyn mentions that her scream and facial reaction after being slapped by Regan were due to being pulled too hard by a harness. Linda Blair's screaming was a reaction to being bounced around on her bed. William O'Malley recalled that William Friedkin slapped him prior to shooting and this caused his hand to tremble while blessing Father Karras.

In order to make Max von Sydow appear much older than his then age of 44, make-up maestro Dick Smith applied generous amounts of stipple to von Sydow's forehead, eyes and neck. His facial skin was then manually stretched as liquid latex was applied. When the latex dried, his taut skin was then released causing the film of rubber to corrugate. This daily make-up procedure lasted three hours and was apparently the cause of much anguish for von Sydow.

The studio wanted Marlon Brando for the role of Father Merrin. William Friedkin immediately vetoed this by stating that with Brando in the film it would become a Brando movie instead of the important film he wanted to make.

There were originally many very brief "blink and you'll miss them" cutaway shots in the 1973 release film, intended to create unease in the viewer. For instance: when the priest is dreaming of his mother coming up out of the subway, there is a brief cutaway of a face (Eileen Dietz), painted black and white, grimacing. There are two other places where this image is displayed: when Regan, lying on the bed, turns to look at Father Merrin and Father Karras, and just after the head-turning scene. In the "The Version You've Never Seen", the same image is superimposed over other scenes in the film: the first can be seen on the hood of the stove when Chris MacNeil has just returned home from speaking with the doctors and the lights go out in the kitchen; the next image can be seen in the scene directly following the former, on the inside door of Regan's bedroom when Chris MacNeil goes to check on her after realizing that Sharon wasn't present in the house. The statue of "Pazuzu" (encountered by Father Merrin) can clearly been seen in the background during the exorcism in the original film. The face of the statue is also imposed onto Regan's bedroom door in "The Version You've Never Seen".

The agency representing Linda Blair overlooked her, recommending at least 30 other clients for the part of Regan. Blair's mother brought her in herself to try out for the role.

The demon seen, but not named, throughout this movie is Pazuzu, a demon known in Assyrian and Babylonian mythology as the demon that brings famine during the dry seasons and locusts during the rainy seasons. He was the king of the demons of the wind.

William Friedkin had to take an all-British crew to film in Iraq because the US had no diplomatic relations with Iraq at that time. They were allowed to film on conditions that included teaching Iraqi filmmakers advanced film techniques as well as how to make fake blood.

In A Decade Under the Influence (2003), William Friedkin talks about the original poster that the studio created for the film. It was a drawing of Regan's hand holding the bloody crucifix that she masturbates with. The original tag line was "God help this girl". Friedkin rejected the poster, stating that the word "God" should not be used in a movie tag line.

In The Fear of God: 25 Years of 'The Exorcist' (1998), William Friedkin states that the studio execs would come up on a weekly basis to have a look at the shooting progress. They shook their heads continuously, believing that the movie was total ridiculousness.

The substance that the possessed Regan (Linda Blair) hurls at Father Damien Karras (Jason Miller) is thick pea soup. Specifically, it's Andersen's brand pea soup. The crew tried Campbell's but didn't like the "effect."

Though often cited as one of the most shocking scenes in cinema, the crucifix masturbation scene was actually greatly toned down from that of the novel. In the source book, the scene is much longer, gorier and sexually explicit, with Regan suffering a broken nose, butchery of her genitals, and orgasming.

Ellen Burstyn received a permanent spinal injury during filming. In the sequence where she is thrown away from her possessed daughter, a harness jerked her hard away from the bed. She fell on her coccyx and screamed in pain.

In the scene where the words "help me" arise out of Regan's torso, the effect was achieved by constructing a foam latex replica of actress Linda Blair's belly, writing the words out with a paint brush and cleaning fluid, then filming the words as they formed from the chemical reaction. Special effects artist Dick Smith then heated the forming blisters with a blow dryer, causing them to deflate. When the film was run backwards, it appeared as though the words were rising out of young Regan's skin in an attempt to summon intervention.

During a 1984 reunion of the cast of The Exorcist on Good Morning America (1975), Ellen Burstyn told story of when she was in Tucson, Arizona filming Alice ei ela enam siin (1974) and The Exorcist was opening in that city while she was there so she went to see it. She stated that the scene where Regan has her arteriogram was the part where most people fainted (this is the scene where Regan gets an arterial catheter inserted into her neck). After that scene she saw a woman wobbling up the aisle so Ms. Burstyn followed her. When the woman finally fainted, Ms. Burstyn was at her aid, loosening her collar and talking to her. Then the woman began to come to and Ms. Burstyn realized that if this woman opened her eyes and saw her, this might cause the woman to panic. Ms. Burstyn's exact words were that she might think she was in the Twilight Zone or something. So, Ms. Burstyn asked assistance from another person to help the woman recover.

Audrey Hepburn was William Friedkin's first choice to play the role of Chris MacNeil, and Warner Brothers supported him because of her good critical/commercial reputation with the studio, but she only agreed to do it if it was filmed in Rome. Anne Bancroft was another choice but she was in her first month of pregnancy and was dropped.

During the session where Karras is recording his interactions with Regan, he asks the demon its name (in Latin) and the demon responds with what would could be considered a witticism on its part: "La plume de ma tante" (literally, "The pen of my aunt"). This is a attributed to elementary French language instruction and used in the early 20th century as an example of a grammatically correct phrase taught despite limited practical use. LIFE Magazine in 1958 described it as: "...the most idiotically useless phrase in a beginner's French textbook." In popular culture, the phrase can be used metaphorically to refer to something irrelevant. In this instance, it could be interpreted as the demon telling Karras in a roundabout way that its name is irrelevant - a common motif in stories of Godly agents fighting evil spirits.

Before starting the exorcism, Father Merrin asks Chris whether her daughter has a middle name. In the Middle Ages Catholics used to give their children several names as they believed it would hinder Satan from finding out the child's real name and controlling one's soul.

Linda Blair injured her back when a piece of the rig broke as she was thrown about on the bed.

The most disturbing scene to the majority of viewers was that of Regan having an arteriogram (the first test she had in the hospital). William Friedkin, attributes this to the fact that the procedure itself looked very realistic, the man who played the doctor was an actual neurosurgeon in real life and that Linda Blair was as believable as a young, scared girl undergoing a scary, invasive procedure.

Producers sought to have Jamie Lee Curtis audition for the role of Regan MacNeil but her mother Janet Leigh refused.

The refrigerated bedroom set was cooled with four air conditioners and temperatures would plunge below 30 degrees. It was so cold that perspiration would freeze on some of the cast and crew. On one occasion the air was saturated with moisture resulting in a thin layer of snow falling on the set before the crew arrived for filming.

Adjusted for inflation, this would be the 9th highest-grossing movie of all time.

According to William Peter Blatty, Warner Bros. wanted to change the title of the film after taking a survey which found none of the participants knew what an exorcist was.

The archaeological dig site seen at the beginning of the movie is the actual site of ancient Nineveh in Hatra, Iraq.

There are tales about ominous events surrounding the year-long shoot, including the deaths of nine people associated with the production and stories about a mysterious fire that destroyed the set one weekend. Actors Jack MacGowran and Vasiliki Maliaros died before the film was released.

A filmgoer who saw the movie in 1974 during its original release fainted and broke his jaw on the seat in front of him. He then sued Warner Brothers and the filmmakers, claiming that the use of subliminal imagery in the film had caused him to pass out. The studio settled out of court for an undisclosed sum.

In the arteriogram scene, the bearded man who assists the doctor is Paul Bateson. He was an x-ray technician at NYU Medical Center where that scene was shot and managed to get that small part. In 1979, he was convicted of the murder of a film critic and was sentenced to 20 years in prison. However, he bragged about and was a suspect in the murders of six men whom he said he picked up in gay bars, had sex with them and then murdered and dismembered their bodies and put them into plastic bags "for fun" in 1977 and 78. They were known as the "bag murders". Although investigators believed his story, he was never officially charged and those murders have technically never been solved. Bateson was released from prison in 2004. The whole story revolving the "bag murders" were later fictionalized in Cruising (1980), which is also directed by William Friedkin.

William Peter Blatty said that William Friedkin misinterpreted the head spinning scene. He said Regan's head was described as turning almost all the way around, not literally all the way around, rotating 360° the way it did.

Linda Blair hated vegetables so much at the time that the use of the pea soup actually did make her vomit.

The actual residence in Georgetown that is used for the exterior shots has a rather large yard between it and the infamous steps. The window that leads to Regan's room is at least 40 feet from the top of the steps. This distance would make it impossible for anyone "thrown" from the window to actually land on the steps. In the movie, set decorators added a false wing to the house, so that Regan's supposed window would in fact be close to the infamous steps.

Lalo Schifrin's score was rejected (see also The Amityville Horror (1979)). William Friedkin later said that had he heard the music of Tangerine Dream (who scored his later film Sorcerer (1977)) earlier, he would have had them score this film (from the "Sorcerer" soundtrack liner notes). Friedkin actually hated the music so much that he yelled for the orchestra to stop playing, removed the reels that had been recording the music from the sound desk, and promptly threw the reels into the streets, all in front of Lalo and his wife.

William O'Malley refers to this movie to students as the "pornographic horror film" he once did.

Vasiliki Maliaros had never acted in a movie before. She was discovered by William Friedkin in a Greek restaurant. Her only acting experience was in Greek stage dramas. Friedkin selected her because she bore an uncanny resemblance to his own mother and William Peter Blatty felt she resembled his mother, too.

The original shooting schedule was 85 days, but filming in America lasted for 224 days.

William Peter Blatty based his novel on a supposedly genuine exorcism from 1949, which was partially performed in both Cottage City, Maryland, and Saint Louis Missouri. Several area newspapers reported on a speech a minister gave to an amateur parapsychology society, in which he claimed to have exorcised a demon from a 13-year-old boy named Robbie, and that the ordeal lasted a little more than six weeks. Robbie was born June 1, 1935, resided at 3807 40th Avenue in Cottage City, MD, and was a member of St. James Parish. He entered the seventh grade at Bladensburg Junior High in the fall of 1947, and was removed in the middle of his eighth grade year on January 15, 1949. He had experiences that ended on April 19, 1949. He re-enrolled in the eighth grade at Bladensburg Junior High for the 1949-50 school year, then spent from the fall of 1950 until June 1954 at Gonzaga High School in Washington, DC.

Film debut of Jason Miller. He received an Oscar nomination for his role as Father Karras in this film.

William Friedkin was supposed to attend a dinner the night he received William Peter Blatty's screenplay. Out of curiosity, he started reading the first few pages and ended up missing his dinner engagement completely.

In one scene, the Jesuit president of Georgetown University (Thomas Bermingham) mentions that Father Merrin (Max von Sydow) is at "Woodstock". Audiences may think the reference is to the famous music festival that took place upstate New York in 1969. In fact, the Woodstock in the film is actually Woodstock College, a Jesuit seminary in Woodstock, Maryland. Opened in 1869, the seminary closed one year after "The Exorcist" was released. The Woodstock Theological Center, a nonprofit Catholic theological research institute on the Georgetown campus, succeeded the college and remains operational today.

The "spider-walk" sequence, which was cut from the original version, was reworked for Ruby (1977) and other low-budget films.

Mercedes McCambridge regurgitated on a mixture of chewed, mushy apple and raw egg to produce the sound effect of Regan's projectile vomiting.

The demon mask used in the movie Onibaba (1964) inspired William Friedkin to use a similar design for the makeup in subliminal shots of a white-faced demon.

Mercedes McCambridge and Linda Blair never met in real life.

As advised by a studio executive, director William Friedkin made several cuts to the movie prior to the release, citing that the scenes were unnecessary. This offended William Peter Blatty, the author of the novel and screenplay whom he had befriended, who thought these scenes formed the heart of the movie. Blatty even refused to speak to Friedkin for some time, but they eventually made amends. Many years later, when the immense popularity of the movie warranted a re-release, Friedkin agreed to re-evaluate some of the deleted scenes and put several of them back as a favor to Blatty, creating an extended "Version You've Never Seen". By his own admission, Friedkin tends to see this extended version as his favorite.

Shirley MacLaine turned down the role of Chris Macneill in order to make the similar, though much less successful, The Possession of Joel Delaney (1972).

According to Variety magazine, it was revealed that Carrie Fisher and her mother Debbie Reynolds were contenders for the roles of Regan and Chris MacNeil. Reynolds is mentioned in the film by Lt. Kinderman in jest as playing Desdemona in "Othello."

This movie was originaly to be remade in 2015, but they cancelled.

To entertain and distract Linda Blair during the long makeup process she had to sit through, the crew set up a television near her makeup chair so she could watch The Beverly Hillbillies (1962).

On the DVD-commentary, William Friedkin says that making this film made him believe in demonic possession.

William Friedkin says in the making of documentary that he cast Jason Miller as Father Karras because he had seen him in a stage play and his performance "reeked of failed Catholicism".

In a 2007 poll conducted by the UK's The Times for the Top 50 Scariest Movie Moments, this film topped the list.

In the scene where Regan is masturbating with the crucifix, Eileen Dietz was used for the shot where Regan belts her mother across the face. William Friedkin felt they needed someone with more heft physically to perform the stunt, and the double was shot from the back. The crucifix scene was filmed with Dietz, according to an interview with her in the documentary Starz Inside: Fantastic Flesh (2008).

Despite the studio's fears that the Motion Picture Association of America (MPAA) would give the film an X rating, it got an R, with no cuts whatsoever. The MPAA's decision, according to William Friedkin, was that it was "a brilliant, intelligent film" that deserved to be seen by a wider audience. Regardless, many American cities such as Washington, D.C. and Boston chose to disregard the decision and gave it an X.

William Peter Blatty based the character of Chris MacNeil on his good friend Shirley MacLaine. Prior to the 1973 production, MacLaine attempted to have a movie made of Blatty's novel and interested Lew Grade in backing the project, but the plans fell through.

At one point the search for a young actress capable of playing Regan was so tiring that William Friedkin claims he even considered auditioning adult dwarf actors.

Director George Cukor loudly blasted the film and threatened to resign from the Academy of Motion Picture Arts and Sciences if it won the award for Best Picture. The Academy Awards given to the film were for Best Adapted Screenplay and Best Sound.

Gonzalo Gavira was called on to create many of the special sound effects after William Friedkin recalled his work from El Topo (1970). One of the more memorable sounds, the 360-degree turning of Regan's head, was actually made by taking his old, cracked leather wallet and twisting it back and forth against the microphone.

For the vomiting sequences, Eileen Dietz doubled (uncredited) for Linda Blair, and later sued unsuccessfully for puking credit. Makeup veteran Dick Smith rigged Dietz's facial contours with sheets of heat-formed plexiglass that were secured at the corners of her mouth and behind her head. A camouflaged nozzle anchored in Dietz's oral cavity provided the apparatus through which the "vomit" could be forcefully discharged, fed by supply tubes discreetly embedded in the plexiglass on both sides of her face. Such was the complexity of the set-up that Dietz could barely swallow or close her mouth.

In the scene in the language lab, a white banner is visible with the following letters TASUKETE written in red. TASUKETE means "Help me" in Japanese.

Several scenes were filmed that director William Friedkin would have loved to include in the movie, such as a scene showing Chris and Regan actually visiting some historic landmarks (as Chris suggests they should do in the movie). However, the soundtrack for the scene had gone missing. Another scene showed a possessed Regan slithering over the floor and upsetting several house guests by making obscene gestures with her tongue. The original negative of the scene got lost, and Friedkin refused to use a qualitatively inferior workprint he had of the scene instead.

On the documentary "Raising Hell: Filming The Exorcist" included with the 2010 Extended Director's Cut, author William Peter Blatty reminisces that the supernatural/demonic sequences did not inspire patrons to flee theater, nor were they responsible for nausea in the aisles. The scene in which Regan undergoes carotid angiography, using direct carotid puncture and pneumoencephalography was the moment in the Exorcist which upset theatergoers. This procedure entails cerebrospinal fluid being drained to a small amount from around the brain and replaced with air, oxygen, or helium to allow the structure of the brain to show up more clearly on an X-ray picture.

Stacy Keach had originally been hired by William Peter Blatty to play the role of Father Karras until William Friedkin spotted Jason Miller in a Broadway play. Despite Miller never having acted in a movie before, Keach's contract was bought out by Warner Bros. and Miller was cast in the role.

Brazilian composer Eumir Deodato (famous for his 2001-Also Sprach Zarathustra heard in the movie Being There (1979)) lived in New York City by the time this movie opened, and was informed by friends that a piece of music he composed could be heard on the movie's soundtrack. He initially dismissed the warning, as he believed they were mistakenly identifying Tubular Bells (also part of the movie's soundtrack) as a composition of his own. Eventually, to clear this matter, his lawyer attended the movie with a concealed tape recorder. He recorded the whole movie, and played it back to Eumir over the phone, who finally recognized a composition of his own: "Carly and Carole", heard briefly at the party scene. Eumir's lawyer arranged a meeting with Warner Brother's legal team and asked for the movie to be pulled from circulation, eventually a compromise was arranged after a non-disclosed sum was paid.

Christian evangelist Billy Graham claimed an actual demon was living in the celluloid reels of this movie.

In the novel, the possessed Regan has diarrhea and frequently relieves herself. Because of this she has to wear diapers. It is also frequently mentioned in the book that her bedroom has an almost unbearable stench, like Winston's cage.

During the scene where Father Karras visits Chris MacNeil as she's ironing, the infamous Ivory Snow box featuring porn star Marilyn Chambers can be clearly seen in the background.

Alfred Hitchcock turned down the chance to acquire the screen rights to the novel and also turned down the chance to direct the film when another producer bought the rights to the property.

The Prospect Avenue apartment where the story takes place was once inhabited by the author, William Peter Blatty, while he was a student at Georgetown University. The house was owned by Ms. Florence Mahoney and is at the corner of 36th and Prospect. During shooting of the exterior scenes the crew had to build special sets to allow sunlight in to keep her garden plants from dying.

The film's sound was notable for its bizarre sound effects and, in some instances, sequences were made more eerie by a complete lack of sound. According to a 1974 Rolling Stone article, the sound designers used a variety of recording techniques and realistic, as opposed to electronic, sounds. To create sound effects ranging from scratching in the house to the devilish noises, the sound effects crew recorded beagle dogs, pigs going to slaughter, a woman convulsing and a trapped bee. In one instance, a variable speed oscillator was used to "tune" the buzzing of the bee to various pitches to create a chord cluster spanning four octaves.

The infamous masturbation sequence was trimmed by 12 seconds & the shot of the desecrated statue of the virgin mary in the church was completely cut by the Irish film censor when first theatrically released in Ireland.

Stanley Kubrick wanted to direct the film, but only if he could produce it himself. As the studio was worried that he would go over budget and over schedule, it eventually settled on Mark Rydell, but William Peter Blatty insisted on William Friedkin instead. After a standoff with the studio, which initially refused to budge over Rydell, Blatty eventually got his way.

The ruins in the beginning of the movie are in Hatra, Iraq. These ruins have been preserved over the past 1400 years by various Islamic regimes. In 2014 the Islamic State of Iraq and the Levant (ISIS or ISIL) made threats to destroy this city stating that "graven images were not Islamic" and should not be allowed to exist. On March 7, 2015, Kurdish sources reported ISIS had begun the destruction of this ancient city.

In order to bring some levity to the shoot, William Peter Blatty suggested shooting a scene (not for the movie, but to amuse everyone at the screening of the rushes) in which Father Merrin would enter the house, take off his hat, and reveal himself to be Groucho Marx, a friend of Blatty's. The parody would even go as far as featuring an appearance from the duck from You Bet Your Life (1950). Groucho was keen to do it, but William Friedkin got sick that day and the idea was abandoned.

The last scenes of the movie to be filmed were the first you see in the movie. The opening sequences in Iraq were shot after other principal filming was completed in the United States.

Unless you've read the book, you may not know that when Regan turns her head all the way around the first time and says, "Do you know what she did? Your c***ing daughter?", the demon is imitating Burke Dennings the director who fell from Regan's window. The head turning represents how Burke's head was turned completely around, and the words that Regan as the demon say are telling Chris that Regan killed Burke.

Heavy Metal band Pantera's 1992 album A Vulgar Display of Power was named after the Demon's reply when Father Karras asks him "Why cant you make the restraints disappear?" and the demon replies "That's much too vulgar a display of power".

After filming, William Friedkin brought production to 666 Fifth Avenue.

Ellen Burstyn wore a bracelet in the film with a horseshoe on it, because she had the idea that she wanted her character Chris MacNeil to be "poorly armed" to fight the devil. On the last day of filming, she gave the bracelet to Linda Blair. Several years later they crossed paths on an airline flight to L.A. and Linda was wearing the bracelet that she had given her.

Father O'Malley said he kept getting crazy requests after the movie came out. "I am not jumping out of any window for anyone's cat!"

It is inferred that Reagan was being molested by Burke, Chris' director and friend. This is more obvious in the novel.

Denise Nickerson, who played Violet Beauregarde in Willy Wonka & the Chocolate Factory (1971), was considered for Regan, but the material troubled her parents too much, and they pulled her out of consideration.

The original "Spider Walk" scene showed Regan sticking out a long, snakelike tongue and trying to grab Sharon.

Linda Blair had it written into her contract that she would not wear any of the same demon makeup for Exorcist II: The Heretic (1977) since the experience of doing it in the first film was so harrowing.

Additional problems, recounted by William Friedkin, resulted because both Ellen Burstyn and Max von Sydow were out for weeks, Jason Miller's young son was critically injured during filming and shooting in Iraq was so hot that the some crew members grew ill and had to be replaced. In his interview at the 2006 AMPAS screening, Friedkin said that the two-story house set burned to the ground, causing a three-week delay as well.

The statue of "Pazuzu" was accidentally sent to Hong Kong, before arriving on location in Iraq.

John Boorman had been offered the chance to direct, but declined because he felt the storyline was "cruel towards children". He did, however, accept the offer to direct the sequel, Exorcist II: The Heretic (1977).

Despite playing the title role, Max von Sydow had less screen time than the rest of the main cast.

Although the song "Tubular Bells" is popularly referred to as the Exorcist theme, it is only played four times throughout the film. It's (arguably most famous) opening movement is played briefly as Chris walks home and while Regan is being examined and filmed at the psychiatric hospital. This is also heard during the end credits. Meanwhile, during the scene where Father Dyer consoles Father Karas after his mother's death, another of "Tubular Bells" movements is played as background music. It is easiest to hear as Father Dyer opens the door to leave.

"Entertainment Weekly" and "Maxim" voted this the Scariest Movie of All Time.

It was on this film that William Peter Blatty met his wife-to-be, professional tennis champ Linda Tuero (see Linda Blatty). She'd been hired as an extra.

While he was writing the novel, William Peter Blatty was collecting unemployment benefits.

Al Pacino was considered among other young leading men for the role of Father Karras.

Merrin and Karras repeat the famous phase "The Power of Christ compels you!" together 14 times.

Pazuzu is often depicted as a combination of animal and human parts with his right hand pointing upwards and his left hand downwards.

After he had rejected Lalo Schifrin's score, William Friedkin was in the office of Atlantic Records chief Ahmet Ertegun, when he noticed a copy of Mike Oldfield's just released Tubular Bells and was intrigued by the album cover. He placed it on the turntable and after hearing the opening part decided there and then to use it as the theme for the movie.

There is an actual serial killer in The Exorcist?. Paul Bateson (an x-ray technician by profession) is one of the radiologists present during the carotid angiography scene, several years later he was convicted of murdering film critic Addison Verill, Bateson became the prime suspect in what were known as the "the bag murders" carried out from 1977-1978, in which six male victims were mutilated and dismembered, their remains wrapped in black plastic bags and dumped in the Hudson River. Some of the grisly fragments washed up on the New Jersey shore, others coming to ground near the World Trade Center. These murders were the inspiration for another of William Friedkins films, "Cruising" starring Al Pacino.

There were three separate beds built to do three separate movements.

Max von Sydow was always William Friedkin's first choice to play Father Merrin.

Jane Fonda was offered the role of Chris MacNeil but declined it. This was during the Vietnam War, when she was notorious for her outspoken radical opinions, and it was rumored she had called the movie "a bunch of capitalist ripoff bulls***". However, in his book "William Peter Blatty on 'The Exorcist' ", the author reported that Fonda visited him personally to tell him the rumor was not true. She told him she had turned down the role because she didn't believe in fairy tales.

The scenes showing Father Karras in his room at Georgetown were filmed in Fordham University's freshman residence, Hughes Hall, fourth floor. Hughes was once the site of Fordham Preparatory school. Since there was no elevator at the time, the windows had to be removed in order to accommodate the camera on a crane. Each year, William O'Malley talks about his experience with the movie after students watch it on the same floor where it was filmed.

The second medical test Regan has is a Pneumoencephalograph. A Pneumoencephalograph (sometimes referred to as an "air study") is a procedure in which the cerebral spinal fluid (CSF) is drained from around the brain by means of a lumbar puncture (puncturing the spinal column with a needle and removing CSF). The CSF is then replaced with oxygen or helium to allow the brain to show up more clearly on x-rays. This test was used in the 1970s to detect lesions in the brain. However, it was a very painful test with side effects such as severe headaches and vomiting due to the loss of CSF (which is replenished by the body in less than a day). The patient also had to be moved frequently while the x-rays were taken in order to displace the air which caused more discomfort to the patient. Furthermore, it relied on plain x-rays which do not clearly represent soft tissues such as the brain. While this test was used a lot before and during the early 1970s, it had limitations. The test did not show actual lesions unless they were on the edge of the structures that could be seen on the x-rays or large enough to displace tissue which could be seen on the x-rays. So, there could be a lesion there, but too small to be seen. Imaging contrast was not part of this test but used in a test that was often performed along with the Pneumoencephalograph called an Angiograph in which contrast was introduced into the vascular system and x-rayed. The Pneumoencephalograph was phased out in the late 1970s when more modern neuroimaging equipment became available.

William Friedkin traveled to England to meet with Bernard Herrmann about scoring the film. Herrmann insisted on doing the music in the UK and mailing the tracks to Friedkin. He was swiftly discounted after that. Lalo Schifrin was then appointed but he provided a full orchestral score which was the exact opposite of what William Friedkin had requested. (Friedkin wanted music that would inspire chills and a feeling of dread in the audience.)

The first words the audience hears are "Allahu Akbar".

William Peter Blatty was friends with Shirley MacLaine, and had visited her at her estate, raising her daughter Sachi Parker by herself, surrounded by an entourage of nannies and tutors helping with the process, taking time out here and there to film a movie. This became the inspiration and prototype for Chris and Regan. ( "Maclaine" isn't that far off from " Macneal").

According to Panorama magazine, William Friedkin didn't give Brooke Shields the part of Regan McNeil because "she was too young for the part". It is known that Shields at the time wasn't known as an actress prior to the controversy of a similar film: Pretty Baby (1978).

Laura Dern and Eve Plumb auditioned for the role of Regan McNeil.

William Friedkin originally intended to use Linda Blair's voice, electronically deepened and roughened, for the demon's dialogue. Although Friedkin felt this worked fine in some places, he felt scenes with the demon confronting the two priests lacked the dramatic power required.

The Exorcist is based on the exorcism of Roeland Doe, a case file from the Vatican involving the possession of a boy in 1949 and his exorcism by two Jesuit priests. The names were changed and the gender of the victim to protect the innocent.

One of Lee J. Cobb's last roles before his death. His character, Lt. Kinderman, was brought back for the final film sequel, The Exorcist III (1990), written and directed by author William Peter Blatty himself. For that film, George C. Scott took over the role. Director William Friedkin appears to have approved the idea, as in 1997 he directed 12 Angry Men (1997), in which Scott played Juror #3, Cobb's role from 12 vihast meest (1957).

The film was plagued with problems that caused delays and raised the budget. William Friedkin blamed part of the budget problems on the continuous breakdown of a $50,000 air conditioning unit required to cool Regan's room to sub-zero temperatures for some scenes in which the actors' breath needed to appear chilled. In his interview at a 2006 AMPAS screening, Friedkin noted that when camera lights heated the room, shooting would be discontinued until the air returned to below freezing.

This was the film in which makeup legend Dick Smith hired Rick Baker as his assistant.

The Greek song playing on the radio when Father Karras leaves his mother's house is called "Paramythaki mou" (My Tale) and is sung by Yannis Kalatzis. Lyric writer Lefteris Papadopoulos has admitted that a few years later when he was in financial difficulties he asked some compensation for the intellectual rights of the song.

Alan Alda was offered a role in this movie, but rejected it because he did not like the book.

William Peter Blatty became friends with actress Tippi Hedren in the early 1970s, and she named one of her lions Billy after him. He gave her a copy of his unpublished novel "The Exorcist" and she was so absorbed reading it, that she woke up her then-husband, an agent Noel Marshall, in the middle of the night and told him that he should represent Blatty in publishing the novel and the film adaptation. She took the photo of the author for the first edition novel's back jacket. The 1971 novel became a bestseller and Marshall would be credited as 'Executive Producer' for the film adaptation, also titled "The Exorcist", where he was supposed to receive 15% of the profits. When the film became a blockbuster, Blatty refused to give the profits, since he never signed the written contract, but only initiated it. Marshall sued and the lawsuit dragged on for several years eventually reaching an out-of-court settlement. These were trying years for Hedren and Marshall since they needed the money to feed the big cats for their film Roar (1981), the financial stress would result in their divorce. Many years later, Blatty ran into Hedren at a party and said Hi. She walked away from him, without acknowledging him.

In Islam, Dhimmi is a historical term referring to non-Muslims living in an Islamic state with legal protection. The word literally means "protected person".

The language lab scene was filmed in a room in the basement of Keating Hall on Fordham University's Bronx campus. The same room was used as a Pentagon office in Piinatud geenius (2001).

The scene wherein Father Merrin asks Chris the child's middle name was cut for the 1973 release, but there is still the scene where Merrin exorcises Regan and uses her first, middle, and last names.

The first scene to be shot was of a distressed Karras pacing the corridors of Bellevue psychiatric hospital, agitatedly discussing with his uncle his mother's incarceration.

According to William Friedkin, Paul Newman wanted to portray Father Karras. Newman is mentioned by name in the film.

In 1981 the film was released on video by Warner Home Video, as one of its first UK releases. At the time there was no requirement that videos should be classified by the BBFC, so the video was simply released on the strength of its existing "X" certificate. Contrary to popular opinion, the video version was never included on the Director of Public Prosecution's list of "video nasties" and was never prosecuted for obscenity, testament perhaps to the popularity of the film and the high regard in which it was held. After the Video Recordings Act (VRA) was introduced in 1984 it became necessary for the film to obtain a certificate for video release from the BBFC. The video release was continually delayed on the recommendation of chief censor James Ferman, who advised Warner Brothers against submitting the film for a UK video certificate. A possible 1988 release was also vetoed by Ferman, who cited recent cases of child abuse as the reason. It was finally released on video fully uncut in June 1999, five months after Ferman's retirement as UK censor.

Father Merrin's arrival was filmed on Max von Sydow's first day of work.

A running gag in this movie involves Kinderman asking several people (including Father Dyer) if they would see some movie with him, but they tell him they have already seen the movie. This is somewhat continued in The Exorcist III (1990), as it is revealed that Kinderman and Father Dyer have struck up a friendship, and regularly go to watch It's a Wonderful Life (1946) together.

The original novel ended with Kinderman and Dyer talking about Casablanca (1942), whereas, in the extended cut they are talking about "Wuthering Heights."

Ellen Burstyn was cast after she phoned William Friedkin and emphatically stated she was going to play Chris.

Though he played a Catholic priest in the film, in real life Max Von Sydow was raised as a Lutheran.

Melanie Griffith revealed that she auditioned for Regan McNeil.

With Mark Rydell in active talks to direct, William Peter Blatty urged Warner Brothers executives to watch the just released The French Connection (1971). Blatty had always pushed for William Friedkin to direct and this helped seal the deal.

When she was working as a model, Kim Basinger auditioned for the role of Regan McNeill.

One "conventional wisdom" explanation of possession phenomena is that it is something called "unconscious fraud", where a suggestible person knows the behavior expected in a circumstance where possession could result and then performs it out of the demands of social compliance. The social compliance includes deliberately forgetting the pretense.

Dana Plato claimed that she had been offered the role of Regan but her mother Kay had turned it down. In the book "Former Child Stars: The Story of America's Least Wanted" William Peter Blatty later said that he had "no such recollection" of this actually happening, and that Plato herself may have been the source for this rumor.

William Friedkin's attention to detail was so extensive than an early scene that simply involved breakfast being cooked took over a day to complete because the director wanted to use bacon that wouldn't smoke and sizzle, which in 1972 meant the production had to find very-hard-to-locate bacon that didn't have preservatives in the Washington, DC area.

The song that plays on the radio when father Karras enters his mom's house is "Istoria mou, amartia mou" (My Story, My Sin) by Rita Sakellariou.

According to William Peter Blatty, director William Friedkin also considered Gene Hackman for the role of Father Karras.

Popular belief and parodies give the false impression that Regan throws up on the priests during the exorcism, but she only throws up on Karras once when he first meets her alone. She does, however, vomit during the exorcism: once at Merrin's face covering his glasses and later slowly onto the bed and Merrin's stole.

Bernard Herrmann didn't want to compose the music score for this film, because he felt that Director William Friedkin interfered with him too much. In Susan King's 2011 with Dorothy Herrmann (Bernard Herrmann's daughter), she revealed that William Friedkin had told her father (Bernard Herrmann) that he wanted to see the music every day. Dorothy was looking forward to having a dinner at Hotel Carlyle at that time. When she arrived at the hotel suite, and Herrmann said to not touch anything. Herrmann packed everything in his suitcase, told Friedkin where he could go and then went out to stay with his brother in Washington Heights.

The closing theme, "Fantasia for Strings" by Hans Werner Henze, was previously used as incidental music by the composer in his score for Der junge Törless (1966).

Lee Remick, Carol Burnett and Raquel Welch were considered to play Chris McNeil.

The film cast includes three Oscar winners: Ellen Burstyn, Mercedes McCambridge and William Peter Blatty (cameo uncredited role) and four Oscar nominees: Linda Blair, Max von Sydow, Jason Miller and Lee J. Cobb

The first medical test Regan has is an arteriogram. The second medical test is a pneumoencephalograph.

Geraldine Page turned down the role of the mother that went to Ellen Burstyn.

When Lt. Kinderman and Father Karras begin their first conversation, says that Karras looks like John Garfield in the boxing movie, Body and Soul (1947). At the end of their conversation, not having gotten what he wanted, Kinderman jokingly says that he had lied and that Karras looks like Sal Mineo. The joke is that Garfield played rough, tough, hard-charging characters with hearts of gold, and he was immensely popular with female fans. In contrast, Mineo was slender, played less manly characters, and was far less popular with the ladies.

Other directors that Warner had approached included Arthur Penn (who was teaching at Yale), Peter Bogdanovich (who wanted to pursue other projects, subsequently regretting the decision) and Mike Nichols (who didn't want to shoot a film so dependent on a child's performance). The studio actually hired Mark Rydell but William Peter Blatty insisted on William Friedkin.

William Friedkin considered Roy Scheider for the role of Father Karras, but for some reason, William Peter Blatty vetoed him.

The two priests - Father Merrin (Max von Sydow) and Father Karras (Jason Miller) - do not meet until 1 hour and 41 minutes into the film (director's cut).

Barbra Streisand declined the role of Chris McNeil.

William Peter Blatty had filed suit against Warner Bros. and William Friedkin over credits and for being barred from production. Friedkin claimed that Blatty was only barred from post-production and that Blatty wanted the credit line, which was added prior to the picture's release: "William Peter Blatty's The Exorcist." Executive producer Noel Marshall stated that Blatty had dropped the suit against the studio but still had plans to bring a suit against Friedkin over credits and being barred from post-production.

Regan was one of the wicked daughters who betrays the title character in William Shakespeare's "King Lear".

Sharon Stone was considered for Regan McNeil.

In one scene, Lt. Kinderman makes a comment that Father Karras looks like Sal Mineo and a little earlier Karras said he confused Kinderman with Paul Newman. Lee J. Cobb, who plays Kinderman, previously appeared with Newman and Mineo in Exodus (1960).

The giant demonic statue that Father Merrin sees at the beginning is Pazuzu.

Kay Lenz turned down the role of Regan McNeil because she didn't like the script. William Friedkin decided she was too old.

Ken Nordine was considered for the demon's voice, but William Friedkin thought it would be best not to use a man's voice.

According to DP Owen Roizman, all of the spectacular visual effects in the film were created in-camera.

In an interview on the January 12, 2007 broadcast of the Mr. KABC radio program it was revealed that actress/comedienne April Winchell was being seriously considered for the part of Regan MacNeil; however, she had developed a serious kidney infection which caused her to be hospitalized and ultimately taken out of consideration.

Among the myriad television spoofs of this movie was an episode of The Odd Couple which featured Felix and Oscar battling a possessed air conditioner. It was called The Exorcists.

The Exorcist was the most popular R rated film of all time when it came out.

Kane Hodder's favorite film.

Included among the "1001 Movies You Must See Before You Die", edited by Steven Schneider.

The sound effect for Regan's infamous head turning scene was accomplished by Gonzalo Gaviria, The sound editor on EL TOPO (1970) by holding an old leather wallet up to a microphone and twisting and turning it in his hands.

Parapsychologist and Occult/Supernatural Expert Christopher Chacon was utilized by Warner Brothers to promote the release of the 25th Anniversary Edition.

In the novel, the MacNeils are not Catholic.

Early in the film, a man is seen wearing a Montreal Canadiens hat. The Canadiens won the Stanley Cup in June 1973, six months before the release of the film.

Jason Miller's Best Supporting Actor Oscar nominated performance was the only one in the category in a Best Picture nominee that year.

Features the only Oscar nominated performances of Jason Miller and Linda Blair.

Pamelyn Ferdin, a veteran of science fiction and supernatural drama, was a candidate for the role of Regan, but was ultimately turned down because her career thus far had made her too familiar to the public.

Though veteran cinematographer Owen Roizman (The French Connection (1971), Televõrk (1976)) is credited as the sole cinematographer of this film (and, furthermore, was the sole cinematographer nominated for the Academy Award for the film), William Friedkin has revealed that, owing to international relations with the British, Billy Williams, who shot Women in Love (1969) for Ken Russell, was actually the cinematographer who traveled to Mosul to shoot the opening Iraq prologue sequence of this film.

Jill Clayburgh auditioned for the role of Sharon.

The Bad Seed (1956), Village of the Damned (1960), The Innocents (1961) and Rosemary's Baby (1968) are all precursors to the film in the development of the whole demon child genre.

Favourite film of Mark Kermode.

In the soundtrack liner notes for Sorcerer (1977), William Friedkin said had he heard the music of Tangerine Dream earlier, he would have had them score this film.

Included among the American Film Institute's 1998 list of the 400 movies nominated for the Top 100 Greatest American Movies.

Jack Nicholson, Dustin Hoffman, Warren Beatty, Burt Reynolds, Ryan O'Neal, Peter Fonda, Al Pacino, Jon Voight, Robert Blake, Christopher Walken, Alain Delon, James Caan, Roy Scheider, Paul Newman, Marlon Brando, Elliott Gould, Alan Alda, and George Hamilton were considered for the role of Father Karras.

Primarily in the infamous scene where Regans bed is shaking a Charlie Brown figure can be seen with a blue baseball cap sitting on Regans right bedside table, and can also be seen on one Lobby card that came in The Exorcist 25th anniversary Widescreen VHS box set that came out in 1998.

Goblin's tubular bell with a rock backdrop theme song to Suspiria (1977) owes more than a small debt to the Exorcist theme song.

Anissa Jones auditioned for the role of Regan, but she was rejected.

Pamelyn Ferdin, a veteran of science fiction and supernatural drama, was a candidate for the role of Regan.

This film loosely inspired The Bollywood Blockbuster horror movie 1920 (2008).

The only film that year to be nominated for Best Supporting Actor and Best Supporting Actress Oscars.

In 2015, the Massachusetts-based wrestling promotion Beyond Wrestling's top heel faction was called Team Pazuzu.

In a behind-the-scenes documentary, William Peter Blatty addressed the extreme reaction of some audience members: "I will tell you about what I believe is the sole cause of all those stories about people getting nauseous, people fainting, people screaming, people running out of the theatre and all that. It was not any of the horror that was taking place. It was, in fact, the medical science that was taking place." This was a reference to the scene in which Reagan undergoes an arteriogram, which involves a needle being inserted into her neck.

When Fsther Karras is listening to the tape of Pazuzu's voice in his dorm room, you can clearly hear the voice say "Merrin" twice. This is Max Von Sydow's character's name and suggests that the two have met before.

Trailer narrated by Percy Rodrigues.

Jason Miller was the only Best Supporting Actor Oscar nominee that year that was from a Best Picture nominated film.

The only Best Picture Oscar nominee of the year to be also nominated for Adapted Screenplay.

William Peter Blatty: The writer of the novel can be seen in the film during the filming scene, standing next to Burke Dennings with a large moustache and wearing a moleskin jacket.

Elinore Blair: The nurse who comes into Dr. Taney's office after the arteriogram is Linda Blair's mother.

The demon that possesses Regan MacNeil is named Pazuzu in the script, but this name is never mentioned in any cut of the film. During the film Pazuzu lies to Father Damien Karras claiming to be the Devil/Satan. Conversations with Father Lankester Merrin show this claim to be false.

The sound of the demon leaving Regan's body is actually the sound of pigs being herded for slaughter. This alludes to a story in the New Testament where Jesus cast out several demons, collectively called Legion, from a man and transfers them into the bodies of pigs. The pigs are then drowned, similar to Father Karris dying after accepting the demon.

In 1985, when Joel Schumacher was filming St. Elmo's Fire (1985) at Georgetown, and attempted to get permission from the Jesuit priest faculty at that school to film there, he was rejected. Schumacher complained to the faculty: "You let Bill Friedkin film 'The Exorcist' here in '73, and one of the characters in that movie said ,'Your mother sucks cocks in hell!'" One of the Jesuit priests answered, "Yes, but the devil didn't win in their movie".

The "Exorcist steps", 75 (or 74 - one is very small) stone steps at the end of M Street in Georgetown, were padded with 1/2"-thick rubber to film the death of Father Karras. The stuntman tumbled down the stairs twice. Georgetown University students charged people around $5 each to watch the stunt from the rooftops.

Director William Friedkin went to some extraordinary lengths to get realistic reactions from the cast. He fired off guns behind the actors to get the required startled effect. When Father Dyer is attempting to administer last rites to Father Karris, Friedkin was not satisfied after several takes. He took William O'Malley aside and asked, "Do you trust me?" O'Malley said yes just in time to get slapped across the face. Friedkin immediately said, "Action!" and the result is in the film. He even went so far as to put Linda Blair and Ellen Burstyn in harnesses and have crew members yank them violently.

Although Mercedes McCambridge provided Pazuzu's lines from the moment when Karras confronts the possessed Regan for the first time up until the final confrontation, Linda Blair and Ron Faber also provided lines for Pazuzu. Blair's voice can be heard when the possessed Regan screams "Fuck me!" in a raspy, high-pitched voice. Faber provided two lines in this same scene, but he also recorded Pazuzu's lines during the entire "demonic head-spin" scene and he also provided a growl in the sequence where Karras is possessed by the demon.

The entire exorcism scene, from start to end, lasts 9 minutes.

Besides Mercedes McCambridge's lawsuit for credit on the film, Eileen Deitz also charged that she played the role of the demon during the exorcism scene. Director William Friedkin denies this, and has cited that Deitz's actual screen time is less that one minute, as she served as little more than a body double for Linda Blair. Nevertheless, Deitz, as of 2014, continues to promote herself as "Captain Howdy," the demon from this film, in interviews and at horror conventions around the world.

When Karras falls down the stairs, the words "fight pigs" are spray-painted near the stairs. In the Gospel of Matthew, Jesus exorcises a man, upon which the demons beg to be cast into a herd of pigs. Pigs (a slang term for police) are also referenced on protestors' signs during the movie set scene.

Body count: 4.