Factual error: In the opening shot of the film, a big oak door opens - carved in it is the date 1862 - 42 years after George III died.
Factual error: Thurlow tries to blackmail Fox by showing him evidence that the Prince of Wales has illegally married Maria Fitzherbert. In reality, Fox - who had been kept in the dark by the Prince - learned the truth about the marriage in 1787, the year before the film's action begins.
Factual error: Early in the film, the King is fretting about the Colonies and he places his hand on a globe that shows the Louisiana Territory (purchased 1803) and Oregon (claimed as a result of Lewis & Clark expedition 1804-06) as part of America. It has already been established that the year is 1788.