Continuity: When going into formation on the Trojan Beach, Achilles has a flaming arrow stuck to his shield. In the shot from Achilles' point of view, the arrow is nowhere to be seen. It is then directly in the line of Achilles' sight again as Achilles and his army move out of formation to attack.
Revealing mistakes: When Achilles introduces his cousin, Patroclus, to Odysseus, King of Ithaca - his wooden training sword is in the foreground. The tip and edges are worn, revealing that the sword is in fact plastic and simply painted to look wooden.
Audio/visual unsynchronized: Throughout the film when Hector, Paris, Achilles and Menelaus all draw their swords, we hear the metal scraping as they are pulled from their shields - Yet we can see that the interior of the shields are cloth lined and the loops that hold the swords are leather, not metal.
Revealing mistakes: Just before Achilles says "You gave me peace in a lifetime of war", the camera is focused on Briseis's hair where the netting from her wig/extensions is clearly visible.
Anachronisms: There are modern clasps on the necklaces and French hooks on the earrings.
Errors in geography: After Achilles rescues Briseis from the Greeks' branding iron in the dark and spend the night together, the next shot shows the sun rising over the sea...to the west.
Revealing mistakes: When the sun is shown rising over the sea, there are no shadows. The shot has clearly been filmed at magic hour and the sun superimposed later.
Miscellaneous: When Briseis is asking Achilles if she is still his captive, the tan line from her bikini is very visible.
Incorrectly regarded as goofs: To kill Hector, Achilles uses a spear. When Achilles is dragging Hector back to camp, we can still see the spear sticking out of him. In the next shot, when Achilles is within the camp, the spear in Hector is gone. Hector is dragged for many miles, it is very likely that the spear either snapped off or fell off by the time he reached the camp.
Continuity: When Paris first shoots Achilles, half of the arrow goes clear through his heel. Later, when Achilles is dying, the entire arrow is only protruding out of one side of his heel.
Miscellaneous: After the Trojans were ordered to push forward after the Greek's first attack, blood can be seen suddenly appearing on a few of the Greeks shields.
Anachronisms: When the Greek leaders are lining up to offer gifts to Agamemnon, one of them is carrying a red-figure vase shaped like a submarine. Red-figure pottery (made of red clay with a black glaze, from which lines and shapes are removed to make red images) was not made until the fifth century BCE.
Errors in geography: In the first scene of Troy, you can see Llamas. These animals are originally from South America and did not exist in Troy.
Errors made by characters (possibly deliberate errors by the filmmakers): When the boy goes to find Achilles for him to go fight the enormous warrior from Thessaly he tells him that "the Thessalonian is huge". He should have said "Thessalian". A "Thessalonian" would be someone from Thessaloniki, a city that was not founded until centuries later (4th century BC) by Cassander, who became the king of Greece after Alexander's death. Cassander married Thessalonike, Alexander's sister and named the city after her to honor her.
Revealing mistakes: When the Spartan ships are arriving in Troy, the bells are ringing and everyone is going crazy. Hector hands his child over to his wife and it's a plastic baby doll.
Revealing mistakes: Obvious dummies used for the bodies of the main characters that are burned, such as Hector, Achilles, Menalaus and Patroclus.
Continuity: While Paris is fighting Menelaus for Helen's hand, their shadows are opposite. This would mean that the sunlight was on both of their lefts as they face each other. They do not match up and the scenes must have been shot at different times of the day.
Revealing mistakes: When the soldiers of Greece are collecting the wood for the Trojan horse, you see bits coming of the wood, revealing the white Styrofoam used to make the wood.
Continuity: When Paris goes forward to talk to Hector on the ship to Troy, his cloak is wide open at the top. During the rest of the scene, the top closes up without him touching it.
Anachronisms: The umbrella used to shelter Paris and Helen during the parade in Troy is obviously modern, as it includes metal spokes like modern umbrellas.
Revealing mistakes: In the raid of Troy, several soldiers can be seen as merely acting out the stabbing of people.
Continuity: When Paris enters Helen's room after the dinner, he gently pulls her hair so that it all lies on her back, behind her shoulders, exposing her neck. When she gets up, it is around/in front of her shoulders again which could have happened while getting up but then after a quick shot to Paris, Helen once again has her all of her hair tucked back behind her shoulders.
Continuity: When Priam meets Achilles in his tent after the battle with Hector, Priam's cloak on his left shoulder repeatedly changes position (folded over or smooth) throughout the scene.
Revealing mistakes: When the Greeks first charge Troy, soldiers run toward the city walls carrying spears. Some soldiers' spear tips can be clearly seen to be wiggling, indicating soft rubber props.
Anachronisms: Helen sutures Paris's wounds after his duel with King Menelaus. Suturing wounds did not become common practice until thousands of years after the movie is set.
Anachronisms: Most equipment used by the Greeks, such as the large round shields and Achilles helmet, is from the Classical Period (5-4th centuries BC). At the time when the epic is set, the Greeks used small bowl-shaped helmets and light leather shields shaped like the number 8.
Continuity: When Helen is telling Hector that she is going back to the ships, her hair style changes between shots.
Revealing mistakes: When Hector removes his helmet right after Achilles does (during their fight scene), you can see the nose bridge and flanks of his helmet move in an obvious rubbery way.
Revealing mistakes: Troy faces west, but the sun can be seen coming up in front of Troy on one of the mornings.
Continuity: When Patroclus is fighting Hector in Achilles' armor, Hector quite prominently stabs him in the chest, which would make a hole or a least a cut in the armor. Yet, when Achilles goes to fight Hector in the same armor, no such marks are visible.
Factual errors: At the time of the Trojan War (circa 1260BC) the inhabitants of Greece did not refer to themselves as Greeks but as Achaians, Danaans or Argives.
Continuity: During the battle of Hector and Achilles, Hector swipes his sword at Achilles's chest, leaving a big scratch on his armour. But when Achilles kills Hector there seems to be no mark on his armour.
Miscellaneous: When Achilles hits Hector with a broken spear, we see the end of the spear that is sticking out of Hector's chest. It is clearly sawn-off, not broken, like it would after Hector/Achilles broke each other's spears.
Continuity: When Hector lifts the helmet off the dying Patroclus, Patroclus' nose is seen to be bleeding. But barely five seconds later, in the shot of the dead Patroclus, there is no sign of a nosebleed.
Revealing mistakes: When the Greeks are sacking Troy towards the end of the film, you can hear a soldier yell "Aqui" twice. Aqui is Spanish for here. Most of the movie was filmed in Mexico and used Mexicans as extras.
Factual errors: When the dead are about to be burned on the pyre - on several occasions - we see coins placed on their eyes. The tradition in these times, however, was to put an "obol" (small bronze coin) in the dead person's mouth for him to pay the ferryman, Charon, for passage over the river Styx to Hades, the kingdom of the dead
Anachronisms: When burning the bodies on pyres, they placed coins on the corpses' eyes. As noted by someone else elsewhere, the Greeks placed a coin in the mouth, not on the eyes. But at the time of the Trojan War, coinage hadn't even been invented yet (it wasn't invented until the 7th century BCE), so there wouldn't have been coins at all.
Continuity: When Hector is dressing for his final battle with Achilles, there are slippers on the floor next to the foot of the bed. During this scene, the slippers change position.
Continuity: During the battle of Hector and Achilles, Achilles kicks Hector to the ground. There is a shot of Hector crawling towards a piece of broking spear. In one shot Achilles throws away his shield and talks to Hector. During this speech, Hector reaches the spear. But after the shot of Achilles walking towards the camera, Hector just reaches the spear and gets up with it.
Continuity: When Achilles' ship hits the beach, several men are hit by arrows and fall into the surf. When the warriors move onto the beach and use their shields as cover, the ship can be seen behind them. There are no bodies in the water or on the beach.
Continuity: Priam forgets to put coins on the eyes of Hector before he is going to be burnt on the pyre.
Continuity: When Achilles is burning Patroclus' body, the moonlight reflects slightly off his arms. While a body is burned, a person with a torch is always beside the one who places the coins, so the firelight would've shined off Achilles' arms as well, and yet it doesn't, indicating that the scene was not shot continuously.
Continuity: In the scene right before Achilles and the Myrmidons take the beach of Troy, Achilles is talking to the men. As the shots go between Achilles and the Myrmidons, the hundreds of ships that should be behind them suddenly disappear and only a bare ocean can be seen.
Incorrectly regarded as goofs: When Paris fights Menelaus and we see Menelaus through Paris' eyes, Paris' helmet appears to have no nose protection. However, the helmet Paris wears in shots portraying him shows a vertical nose protection. This is not a mistake - an object like that slim piece of metal placed directly between the eyes is not visible by the wearer. (Place your finger straight vertically along your nose. If you look straight forward, as Paris was looking at Menalaus, it won't appear to be one object in the middle of your vision, but rather two separate objects, one on either side of your vision.)
Crew or equipment visible: In the Director's Cut during the burning of Troy, just after we see a statue fall forward and break, there is a shot of a temple burning. On the roof of that temple a crew member sporting a motorcycle helmet is seen running across the top right-hand corner.
Anachronisms: In one of the scenes where Brad Pitt's left arm is exposed, his vaccination mark is quite clearly seen.
Revealing mistakes: In the beginning you see a dog walk past several relics of a battle. This includes a dead horse. However you can see it blink and move it's ear even when all other items suggest the battle to be long past.
Continuity: As Patroclus enters Achilles' tent to ask if he will join the Greeks to fight the Trojans, Achilles is seated while eating and drinking. In disgust at Patroclus, Achilles dashes the contents of his cup on the fire. Moments later, he drinks from the empty cup.
Crew or equipment visible: Obvious camera shadow on the ground during the Bana-Pitt bout.
Continuity: After the battle in front of the gate of Troy, the field is cleaned. This includes every scrap of flesh, every drop of blood,every footprint, and even some grass is replaced as is seen when Achilles rides up on his chariot to challenge Hector.
Revealing mistakes: During the battle in front of the gate of Troy, the dead are in a line where the two armies clash. The dead are obviously rubber dummies based on how they move when stepped on. Also, no dead are seen towards the rear of the field, where victims of the archers would be expected.
Incorrectly regarded as goofs: When the Trojans invade the shores at daybreak to initiate the second battle, it is quite obvious that Brad Pitt was playing the role of Patroclus until his throat was cut. First, you can clearly see Pitt's face in Achilles' helmet in the close-up shots when he is about to start fighting with Hector. Second, you can see the significant change in Patroclus' physique before and after Hector cut his throat. However, in the actual epic The Iliad, Patroclus is disguised by the gods to look like Achilles until Hector kills him, explaining why Pitt fills the role until Patroclus's death - he is meant to look like Achilles.
Continuity: When Achilles is dragging the dead Hector away from the walls of Troy, the spear in Hector disappears from his body in every long range shot, even though it remains in every close up.
Continuity: As Achilles dies, his sword is seen sticking out of the ground, but when the camera pans upward in the next shot, the sword is clearly now lying on the grass next to him.
Continuity: After Achilles and his men take the temple, Achilles lopes off the head of the golden God statue. Achilles didn't have a sword at the time to do this because he'd just left the sword buried in a Greeks head.
Continuity: When Hector and Achilles have their final showdown, Hector is seen with some sort of string or hair strand extending from just below his helmet on his left. When the scene goes to show him removing his helmet, this item is gone.
Continuity: Before Achilles dies he pulls the arrows out and then drops them in front of himself, but after he collapses the arrows are seen arraigned in a sort of 9, 12 and 3 o'clock position to his body in the areal shot.