Goofs

(at around 1h 12 mins) Immediately after major Granville shoots someone, the camera cuts back to show Father Merrin shouting "No!". In couple of these shots, this character appears as if the weather is raining on him. Not everyone in the shot, just him (left hand side of frame). This occurs at least twice, and for everyone else it's a sunny day. (Freeze-framing confirms the streaks of water.)

(at around 24 mins) Father Merrin cuts his hand lengthwise on a piece of glass. Later, Sarah cleans and bandages his hand. But when we see the bandage, it is going across, not up and down like the wound.

(at around 18 mins) When Merrin enters the church for the first time, his guide hands him a lantern when he steps off the ladder, but after Merrin walks forward, the guide is still holding a lantern. He may have had two, but later, when the second priest comes down, the guide no longer has a lantern.

(at around 23 mins) Sarah has three tarot cards laid out on the table when Father Merrin walks in. They are gone in the next shot, and reappear when he asks about them.

(at around 48 mins) When Father Merrin is in the church removing the top of the secret passageway, he drops his hammer. In the next shot he is still holding the hammer.

(at around 1h 8 mins) When the tribes-people are performing their primitive ritualistic exorcism on Joseph in the infirmary and the demonic presence begins snapping the tribesmen's bones, one of the tribesmen sustains a compound fracture to his shin bone. The tribesman is in agony like the other men in his tribe with broken bones, yet they all "run" quickly out of the infirmary. Even if man with the snapped shin could somehow endure the pain to be able to move, he could not walk, much less run with a completely snapped shin bone. The tribesman would have fallen to the floor and one or more people would have had to lift or drag him out of the infirmary. That didn't happen in this scene. All the tribesmen are seen scurrying out of the infirmary to escape from the unseen presence that had just badly injured all of them.

The troops are Royal Army Ordnance Corps, an odd choice for such a mission. It is the equator and they wear woolen garments over their uniforms (in 100F?) Also the jeep has Royal Artillery markings.

(at around 46 mins) When Merrin looks at Bession's drawing as he is walking into the church, he has it the right way up (with the cross inverted). A few moments later he looks at the hanging cross and realizes he's made a mistake in interpreting the drawing. He looks at the drawing again (now upside down, with the cross the right way up) and turns it around, giving him his epiphany about the hidden passage.

(at around 52 mins) Sarah's hypodermic needle is a lot longer before she injects the boy than it is after she pulls it out. (A trick needle slides back into the chamber of the syringe, instead of into the patient's arm. If it doesn't work properly, then the needle will be shorter after the injection than before.)

(at around 1h 10 mins) When Father Merrin pushes Father Francis against the wall, it wobbles.

(at around 1h 45 mins) In the final shot of the movie, as the priest is walking toward the Vatican, his shadow on the cobblestone falls at a different angle from those on the buildings. According to the background, the sunlight is obviously coming from behind us, but the priest's shadow goes off to the right.

When Merrin is exploring the inside of the church, especially the secret chamber, the lighting very often doesn't match the position of his lantern, nor the type of light a lantern of that style would produce.

(at around 56 mins) When Sarah walks through the hospital with the candle, the light emitted by the candle varies extremely. Then when the light and radio go on, one can clearly see that the candle is just a replica made of plastic.

(at around 1h 19 mins) Father Gionetti gives Father Merrin a copy of the Rituale Romanum (Roman Ritual). (The administration of exorcism is in Title X of the Rituale Romanum.) The title of the book embossed on its leather cover is "Roman Ritual", in English. Later in the film (at around 1h 35 mins), Father Merrin asks Joseph to help him by reading passages of the book, and we are shown a couple of printed pages, the text of which is also in English. The Rituale Romanum would have been printed in Latin in 1949, when the film is set, because vulgar translations of liturgical texts were not authorized until the promulgation of the Sacrosanctum Concilium (Constitution on the Sacred Liturgy) by Pope Paul VI on 4 December 1963, as part of the Second Vatican Council.

(at around 57 mins) When the power is restored in the infirmary the lights and the radio go on simultaneously. In 1949 radios were tube-type and required a warm-up time.

The crucifix hanging upside-down underneath the church resembles Western, Renaissance portrayals more than actual Byzantine depictions of the crucified Christ. In fact, it is even unlikely that a 5th-century church would have had such a crucifix (particularly a life-sized one like in the movie). Firstly, Christian artists were only beginning to portray Christ regularly in such a manner at that time, and when they did, he is not shown as suffering or dead as in later depictions (and the prop in the movie), but triumphantly alive and erect. (In fact, in some contemporary artworks - particularly Byzantine ones - he is even shown clothed with a sleeveless long robe known as a colobium.) Secondly, the Byzantines inherited early Christian distrust of monumental sculpture in religious art and so usually produced only reliefs: a crucifix featuring a fully-sculpted depiction of Christ crucified would have been quite odd.

(at around 8 mins) In 1949, Kenya would have been pronounced "Keen-ya" instead of "Kehn-ya," as it is today. The pronunciation change came about in 1963 when Kenya became independent from British rule. Characters in the movie use the modern pronunciation instead of the old.

(at around 1h 35 mins) When Merrin and Joseph perform the exorcism, Joseph responds "And also with you." This loose translation of the Latin phrase "Et cum spiritu tuo" ("And with your spirit," or traditionally, "And with thy spirit") was only coined in 1973, when the International Commission on English in the Liturgy (ICEL) released an English translation of Latin ritual texts used in the Catholic Church.

(at around 3 mins) Right in the beginning there's a establishing shot subtitled Cairo. In the background you can see the pyramids of Gizeh looming over the city. These pyramids are only about 80 meters high and more than 15 kilometers from Cairo. There's no way to see them anywhere from Cairo at all.

(at around 52 mins) When Sarah is giving Joseph a shot, she gives it in the wrong spot. The needle is the size for an adult intramuscular injection which would be given in the muscular part of the arm. She gave it just a little above the elbow, which is not a very muscular region. It is possible that she would have to use the over-sized needle because of a lack of supplies in the area she was in, but she would never have given the injection in that location if she were medically trained.

(at around 2 mins) When the Byzantine Knight/Priest crosses himself while standing among all of the bodies, he does so in the Roman Catholic fashion (left to right). Any Byzantine of that era would adhere to the Eastern Orthodox variant (right to left).

(at around 5 mins) At the beginning of the film, Father Merrin is told that a church has been found in East Africa and that the church is from around 5 AD. He meant to say that it was from the "fifth century AD".

(at around 1h 25 mins) The machine gun that the British Soldiers set up and use against the African tribe is a German MG42. Although the movie is set post WW2, it is very unlikely that the British Army would have recycled this weapon into their artillery.

(at around 1h 22 mins) When Father Francis takes Joseph into the church, he says "In nomine patris, et filii, et spiritus sanctu". The actual Latin is "In nomine patris, et filii, et spiritus sancti" - "In the name of the father, the son, and the holy ghost".