Factual error: When the Romans fight in Germania, the forest is made up largely of European black pines (Pinus nigra). However the woods there and then should have been mostly beeches (Fagus sylvatica). (00:02:30)
Factual error: The opening battle is wildly inaccurate. The Roman legions were trained to fight as a regimented force, and to maintain formation for mutual support. In the film, the formation collapses instantly upon contact with the enemy. Further, the Roman legions used spears called pila. Doctrine called for them to be thrown while the enemy closed. The Romans would then draw their swords and fight, while remaining in formation. Though the Romans are shown holding their pila in the opening scenes, they are never used against the barbarians, and we see no pila-riddled shields and/or corpses in the background. (00:09:15)
Factual error: When a group of soldiers goes to Maximus' villa to burn it and kill his family, his son points them, saying in Italian "Mamma! I soldati!" ("Mom, the soldiers!") and then "Papà!" ("Daddy!"). This is because the young actor (Giorgio Cantarini) is Italian and they didn't translate, for some reason. As a result, he's speaking Italian in a movie in English, where people are supposed to speak Latin, in a province where Italian was never ever spoken. (00:43:07)
Factual error: Architectural elements were from several centuries later. Note the balustrades, bell towers and domes in the Rome skyline shot and, more than anything else, Maximus' house, a typical 15th century Chianti villa. Also the columns are not painted, which they were in ancient Rome. (00:43:10)
Factual error: In the scene where Maximus is finding his wife and son's bodies there are two chickens to his left. One of these is definitely a Rhode Island Red hen. This breed of chicken was developed upwards of 1,700 years after Roman times in the US state of Rhode Island. (00:44:10)
Factual error: The last gladiator to be killed when Maximus is chained to Juba holds a trident. This kind of gladiator is called a "retiarius." They're also the ones who fight using nets. The shoulder armour was always worn on the left shoulder, not the right, because left-handedness was frowned upon in Ancient Rome. Also "retiarius" never wore face masks for helmets as it would give them too much of an advantage. Every Gladiator was given equal advantage depending on their specialty. (00:55:25)
Factual error: In one of the scenes in Rome leading up to a fight, leaflets are being handed out. These didn't exist, event notices were written up on boards. (01:02:15)
Factual error: There's a blackboard in one of the scenes when there's about to be a gladiatorial contest. The Romans may have had blackboards then, but the writing on it is wrong. The sort shown takes time to chip into stone used on statues, etc, and I suppose it would take quite a long time just to write things on a blackboard. The Romans had different writing for things like that, as shown in the graffiti in Pompeii. It's more flowing, and I expect it's quicker to produce. (01:15:00)
Factual error: Before Maximus enters the colliseum, he selects a helmet and places it on his head. On the rack is a copy of a saxon helmet found at Sutton Hoo, England and part of the treasure found at that location. Unfortunately this is a 7th century design. (01:17:45)
Factual error: In the arena, Maximus tells Commodus and the Roman spectators that he is "general of the Felix legions." The problem is, there was just one Felix legion, namely Legio IV Flavia Felix. (01:27:35)
Factual error: During a meal in the gladiatorial school, Juba is shown eating with a metal spoon. Slave-gladiators almost certainly only ate with their fingers, wooden spoons, or wads of bread to sop up their food. They never would have access to metal spoons that could be sharpened and used to attack the guards keeping watch over them. (01:36:20)
Factual error: When the execution squad is ready, Quintus says "fire". Of course this is incorrect, since you don't fire a bow and arrow, but "loose" it. The term "fire" came only with the invention of firearms. It's a common mistake in bow / arrow type situations. (Extended version only). (01:47:10)
Factual error: The snake with red-yellow-brown skin you see in a night-shot in Rome is a Pueblan Milk Snake (Lampropeltis triangulum campbelli) from Mexico, also found in southern Texas. Not quite right for Rome... (02:04:15)
Factual error: When Maximus walks through the wheat field it is obvious (to a botanist) that the wheat shown is an octaploid variety which was developed in the 1950's for the Green Revolution. The type of wheat grown during Roman times can still be found in many areas too, so it's not like the filmmakers can't find it. (02:19:45)
Factual error: At several points in the movie you will see speeches to a large crowd. These take place at the Piazza San Pietro. This square however is late Renaissance. Connected with this is the columns you see in these scenes. They were designed by the Italian artist Bernini, and the film crew didn't even remove the statues of all the popes.
Factual error: Women were not allowed to be mixed with men. Only Vestales could stay where men were. Women could see the games just from the last ring-level of the Colosseum.
Factual error: Several men, most notably Marcus Aurelius, are long-haired (for male standards) in the movie. In Roman fashion, men were expected to use their hair short. Male long hair was seen in a very bad light, especially for an emperor.
Factual error: There are several points in the film that show horses with saddles and stirrups. Pretty odd as the stirrup didn't arrive in Europe from China until the 3rd or 4th Century at the earliest.
Factual error: Early in the film Maximus walks through a cereal crop trailing his hands against the heads of grain. Except that dwarf varieties of cereal were only bred in the 20th century. Before this a crop would have been up to a man's shoulders.
Suggested correction: No doubt the scene was shot with a modern variety, but it turns out that it is a good approximation of the wheat grown at the time of the story. Two varieties of wheat grown in ancient Rome, the Emmer and Eikorn varieties, reach only 2-3 feet at maturity. These were originally wild wheats that had been cultivated for 8-10 thousand years BCE.
Factual error: As the Gladiators are being led into the Colosseum for the first time, an elephant is led across the background. Although the Romans used elephants in the arena, they used African elephants, and the one we see is an Asian elephant.
Suggested correction: This movie is not based upon facts. Many element were fictionalized. This is just example of fictionalized things.