Robin shoots Will in the hand, but later when Will asks Marion to dance and offers her flowers, the wrong hand is bandaged.
When the boat takes Marian and Duncan away from the camp, Sarah isn't in the boat with them.
When Locksley is writing his letter asking for news of his son, he says "Were you present at his capture near Jerusalem?" but when we see the close up of the letter, it reads, "Were you present at his capture near Acre?"
When Robin and Wulf are having a competitive target practice, Wulf's hair is shaggy looking on both sides of his head. But in the close-up of Wulf taking aim, the right side of his hair is slicked back so that Robin can tickle his ear with the feather from the arrow.
When Friar Tuck makes his escape from the camp, he is knocked down by a low branch, breaking the wooden arch above him. When he later pulls the cart back to the camp, the arch is intact.
When Robin begins training the outlaws, we see an arrowhead being cast, outdoors in a small mould. Next, we see an iron/steel arrowhead being shaped on a stone. Iron or steel could not be cast, outdoors and in the small quantity as shown, due to the heat needed. The metal shown can only be pewter, lead or tin. To produce arrowheads in those conditions, a friendly blacksmith would beat out a suitably thin piece of waste metal, chop pieces off, then, others could file or rub them to shape and sharpness.
Toward the end, Azeem is about to shoot a flaming arrow at an explosive barrel. The guard ties a rope around Will's neck and forces him down on to the barrel, and Azeem blows out the flaming arrow. If it were that easy to extinguish the arrow, it never would have stayed lit during fight.
The Sheriff's scribe tells him that Robin and his men have looted money from them for about five months. Assuming that the looting started about the time that Robin slashed the Sheriff's face, his scar shouldn't still be red or still be stitched up.
When King Richard appears at the end, Robin addresses him as "Your Majesty". At the time, kings were "Your Highness" or "Your Grace"; Majesty was only introduced in about 1519, by Henry VIII, not to be outdone by Charles V, the Holy Roman Emperor, who began calling himself Majesty in that year. The three terms were used arbitrarily even under Elizabeth I.
King Richard is portrayed as an old man, with a gray beard and played by 61 year old Sean Connery. In reality, Richard was only 37 at the time the film is set.
Words and phrases which did not exist in 1194 are used by characters, and Robin has an accent which doesn't fit in. We are presumably hearing a modern translation of what they were really saying.
In the battle with the Celts, nearly every Celt who is hit by an arrow and killed is played by stunt coordinator Nick Gillard, who thus dies several times as different characters. If you look carefully you can recognize him.
While rescuing the boy, Robin grabs a crossbow and throws it at one of the soldiers, "hitting" him in the face. The crossbow hits Plexiglas in front of the soldier, and leaves a scratch that is momentarily visible.
When Robin Hood is kneeled swearing on his father's grave to revenge his death, he cuts himself in the hand, and we can see the blood trickle through his fingers.
Immediately after, when he is standing up, both his hands are completely clean, the blood has disappeared.
After Wulf is saved from the Sheriff's men and runs off, Azeem walks around the rock wall and casts an unnaturally sharp, dark shadow (lighting error), despite having complained about there being "no sun in this cursed country" and it being visibly overcast outside.
When Robin shoots the arrow that goes through Will's hand the wire/string that the arrow is fired along is visible.
At the wall when Robin saves Wurf you can see Morgan Freeman climbing back up wall as if to back into his starting position.
When Maid Marian in disguise fights Robin Hood, Robin slams her hand against a wall and it clearly buckles as it is made of plaster. A small crack in the faux stone wall is formed.
When Fanny demands to help rescue Wulf, she reminds John that she's "birthed eight babies", and John tells her she "should be minding the other seven." In the 12th century, infant mortality was slightly over 25%, and child mortality just under 50%. It is unlikely that all eight of Fanny and John's children are still alive.
As the Sheriff's Men are hanging a Wanted Poster an arrow hits it, then Little John walks over and rips it down with no visible tare or hole in it from the Arrow.
In the very next shot (Facing the Sheriff's Men), The Poster is back up, Little John is missing, and there is No Arrow stuck in the Wanted Poster.
The Celtic mercenaries are from the culture of several centuries prior to the film's setting.
Mortianna's black magic altar includes a cloth decorated with a pentagram, and an inverted cross. These symbols only became associated with witchcraft in relatively recent times, however. In the Middle Ages an inverted cross was known as a St Peter's Cross because of the tradition he asked to be crucified upside down, as he believed he was unworthy to die in the same manner as Christ. It was considered a symbol of Christian humility and was also used by Peter's successors as head of the Church, the Pope. The Pentagram was a common device used in the Middle Ages to represent the Five Wounds of Christ.
All marriage scenes invariably use the wording of the Book of Common Prayer, which was written in connection with the Reformation several hundreds of years later. In 1194, all clergy would have been Catholic and said the Mass in Latin at weddings.
Azeem is shown using a refracting telescope, which was not invented until the 17th century.
Black powder, or gunpowder was not known to the Arabs until some time between 1240 and 1280. Azeem would have had no knowledge of it in 1194.
When Robin is giving Marian a tour of their hideout, they walk past a waterwheel and Robin says, "It works - sort of." Azeem replies, "Of course it works," but his mouth doesn't move.
When Robin is being attacked in Marian's home, Azeem tries to break down the door. Duncan cries out "Point me toward trouble Azeem, I'm ready!" - but his mouth isn't moving.
When Peter falls into the dirt after being hit by an arrow in Jerusalem there is a wooden thump.
Before Robin enters the bishop's private chamber he places his rings into a gold dish with black circle on it. Later the same dish appears in Robin's treasure room behind Mariam.
When the men are pushing the catapult to the gate, look at the far left of the screen - for a second or two a camera and cameraman is visible.
A crewmember is visible from a second story window when the catapult is being moved near the end of the movie.
The shadow of the cameraman can be seen as Robin runs across a room near the end of the movie.
During the opening of the campfire scene, after Robin's fight with John Little, a long metal ladder is visible on the ground to the right of frame.
When Robin and Azeem arrive in Dover, Robin says we will be dining with my father by nightfall. Nottingham is over 170 miles from Dover. Robin then makes an extravagant detour via the "Robin Hood" gap in Hadrian's Wall (approximately 120 miles north of Nottingham) before heading south again; making a rather unlikely journey total of more than 400 miles in under a day.
The outlaws' hideout in Sherwood Forest is taken by surprise by large catapults, despite the density of the forest.
From a distance, Sherwood Forest appears to be coniferous, but up close it is deciduous.
Mortianna has a boa constrictor, native to the Caribbean and Central and South America in her chambers.
When the film first introduces Marion, she fights Robin with an impressive display of advanced sword fighting skills, almost demonstrating ninja like abilities, and Robin is only able to beat her by a combination of burning her and then being distracted. She then resorts to being a fairly feeble physical threat for the rest of the film and is easily subdued by any other character with very little defence offered.
Duncan and the Sheriff's men are reluctant to enter Sherwood Forest because it appears widely believed to be haunted by evil spirits, but there are no shortage of travelers for Robin and his men to rob.
Azeem demands Robin tell him which way is East so that he may pray. However, as a Muslim, he would want to know the direction was Qibla (toward Mecca). In England, this would be almost exactly southeast.
A Muslim prayer begins by standing upright and bringing his hands up to his ears and not in a squatting position like Azeem does it.