Factual error: The daylight air-raid on the Norwegian Heavy Water plant in 1942 was done by Boeing B17G bombers, with the distinctive chin gun turrets. These planes did not come into service until 1944, when they were introduced to counter the head-on attacks by German fighters.
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: Many of the panoramic scenes in this film capture breathtaking views of mountain ranges completely covered with snow - a geographical feature not to be found in the Holy Land. It is found on occasion, though, in Arizona, where these sequences were actually shot. Other scenes show desert bluffs, mesas and arches that are also not found in the Middle East: they're the distinctive formations of the Arches National Park in Utah, USA.
Factual error: Rifles and more so, cannons of the type shown in the movie were not close to being invented in the 1500s.