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: In the last battle scene when you see shots of the German destroyer through the periscope the last one shot before it's blown up is really bad angling. The ship is far away but in the scope it's very close and the periscope (in order to get that camera angle) is 100 ft in the air.
Factual error: In the scene at Lord Cornwallis' outdoor party celebration, right after Benjamin Martin and his Continental Army blows up a British Ship, one of Lord Cornwallis' Captains throws back a big gulp of his drink from his Martini glass in grief and disbelief - the problem is this movie takes place in the mid 1700s and the Martini Glass wasn't invented until the 1920s, during the Roaring Jazz days.
Factual error: During the "Vietnam Scene" at the beginning you see a very long take of an AK47 muzzle appearing slowly from a bush.The problem is, it has the slopping muzzle brake of the AKM, not the plain muzzle of an AK47. The AKM was not in service in 1968, and was never supplied to North Vietnam anyway.
Factual error: When they are on the pistol range, the recruits are shooting with a "modern" two handed grip. In 1971, the US Army still taught recruits to shoot one-handed.
Factual error: When we see the battle zone from the hovering helicopter, among the shot (Centurion) tanks one can spot one or two Merkava Mk. 1 or Mk. 2 tanks. The Merkava Mk. 1 entered service in 1979, six years after the movie takes place. The Mk. 2 entered service in 1983. (01:34:00)
Factual error: Throughout the film, you hear Lina Termini's "Ma L'Amore No" playing on the gramophones. However, "Ma L'Amore No" was released in 1943 - three years after the film's setting. (02:02:00)