Factual error: At the beginning of the movie, Robert E. Lee addresses Francis P. Blair as 'General' once. Blair however was never a general and in fact never held any military rank.
Factual error: The song that Davy Crockett plays on the violin is 'The Mockingbird Quick-Step,' written in 1855, several decades after the events of this movie (and later used by the 'Three Stooges' as a theme song.).
Factual error: The movie depicts Wes Studi, who is playing the Paiute medicine man "Wovoka," as coming to the Sioux reservation and delivering his vision. Wovoka (aka Jack Wilson) was from Schurz, Nevada 1250 miles away from the Pine Ridge Reservation in South Dakota. He never travelled to South Dakota. What really happened was tribal parties (at great personal risk) travelled to Nevada to get the message and brought it back to the Sioux people. Of course, this message was "modified" somewhat to better fit Lakota culture.
Factual error: The weaponry of the Romans and their use is wrong (as they are in all Hollywood movies playing in the Ancient Mediterranean that I know): Instead of one spear, each legionary would carry two weighted javelins, called Pila (singular: Pilum), which had a long narrow iron head. The purpose of these were to throw them at the enemy before melee; if they did not kill their targets, the pila would get stuck in their shields. The head shaft would bend, making the pila useless for 'return' to their original owners, and with the added weight of the javelin, the enemies' shields were rendered useless as well. Following this, the Romans attacked with short swords (the Gladii; singular Gladius).
Factual error: Two passengers play a piano/vaudeville routine in the lounge for the officers and passengers. During its initial season (1936) Hindenburg had a lightweight aluminum baby grand piano on board. However, passenger accommodations were expanded over the winter of 1936/37 and the piano was removed. There was no piano aboard Hindenburg on her fatal flight in May 1937.
Factual error: Pierrepoint is depicted as having a London accent. In real life, however, he was from the north of England, and had a Yorkshire accent, which sounds completely different. This is proved in a BBC interview with him, dating from the 1970s.
Factual error: A headline from the Pantagraph (an Illinois newspaper) dated 19 December 2001, is shown in big letters to read, "Latest Florida recount shows Gore won election." In fact, no edition of the Pentagraph has ever featured an article that claimed this. The only time those words appeared in that newspaper was in small print over a letter to the editor dated 5 December 2001.
Factual error: Midway through the film, the IRA flying column successfully ambushes a motorised British patrol. Immediately afterwards, when the column's survivors are milling about on the roadway, one IRA man is shown to be armed with a German Mauser Kar 98k bolt action rifle. This is historically incorrect, as this weapon did not go into production until after Hitler's assumption of power in the 1930's - at least thirteen years after the events depicted in the film.
Factual error: Just after the start of the Korean War, McArthur places a map of Korea on the hood of a jeep to explain to a subordinate general his plans to invade Inchon. The map shows the boundary of North and South Korea not along the 38th parallel, which was the border at the time (1950), but along today's DMZ - not established until the Korean armistice was signed in 1953.
Factual error: The film strongly implies that John Dudley, the Duke of Northumberland, keeps his head (literally) by converting to Catholicism. In fact, he was executed well before Lady Jane Grey was.
Factual error: John Smith's (voiced by Aussie, Mel Gibson) accent changes and also fades in and out during the course of the movie.
Factual error: In a picture from the UN headquarters in New York in the year 2003 you see two German flags. The German Democrativ Republic hasn't existed since 1990. (01:16:04)
Factual error: When Lt. Lee shoots down the second Messerschmidt in Italy, you can see it is a twin engine plane.
Factual error: When Mark Felt and the FBI Director are in a car on the way to the Watergate hearings in 1972 or 1973, from the car window, you see the WW2 memorial, which was built in 2004.
Factual error: The main plot of 'The War Lord' is based on a total fallacy. Chrysagon, a nobleman in eleventh century Normandy, falls in love with Bronwyn. She is betrothed to Marc, a villager on Chrysagon's estate. When Bronwyn and Marc marry Chrysagon claims 'Droit Du Seigneur', a law that a lord is allowed to sleep with a lesser man's wife on their wedding night. It is often asserted, even by some medieval historians, that 'Droit Du Seigneur' was legally enforced in the middle ages, but no reference to the practice has ever been found in any surviving medieval law code, legal text book, or historical source. It is first mentioned in the sixteenth century, and then as a discontinued practice from a barbarous past (like human sacrifice or cannibalism) but the earliest accounts of the custom do not provide any verifiable sources, suggesting that it originated in over-active minds of writers of popular romances.
Factual error: Anne Frank received her diary on her birthday, and started writing on it 1 month before she went into hiding. In the movie however, she is presented with the diary on the first she arrives at the hiding place.
Suggested correction: Since this movie is based on actual events and not considered a documentary, then the film-makers are allowed to change things to their liking.
While I feel like this sort-of correction could apply to certain elements of movies based on true stories like dramatized scenes (since there has to be some condensation of time and some elements boosted for drama, which can be chalked up to filmmakers changing things), I think a film based on a true story contradicting a known hard fact like this should 100% count as a mistake. Otherwise, you could just as easily argue that any factual error in any film is invalid because the filmmakers are "allowed to change it."
Factual error: In the opening shot of the movie while our characters are driving down the street in 1951, there is a post-2000, white Toyota Tercel. It's the 2nd car on the left. The car is removed from the next scene. (00:00:50)
Factual error: A concrete barrier is shown around the White House in the 1960's. This was not put into place until the 1980's.
Factual error: Hugh Jackman says the car he is working on is a '72 classic. It is actually a 1979 Pontiac Firebird.
Factual error: The movie takes place during the year 1919. Yet before one of the World Series games the stadium announcer requests that everyone stand up to sing "the national anthem". The US did not have a national anthem until the 1930's when Frankin D. Rosevelt signed into law the Star Spangled Banner as the nation anthem.
Suggested correction: According to Ken Burn's "Baseball", Burns and Ward verify that "The Star Spangled Banner" was sung at a baseball game in 1918 to support the efforts of American Troops in WWI- in which players like Ty Cobb, George Sistler, and Christy Mathewson all fought.
The mistake is saying the announcer called it the national anthem, not that they sung "The Star Spangled Banner."