Factual error: The prince mentions a Danish king of the past called King Gustaf. This is an atrocious mistake. Never has there been a king of Denmark with this name. Many SWEDISH kings have been called Gustaf, but never a Danish. All the royal names in the film are very unrealistic. The names Edvard and Arabella would NEVER be used for Danish royalty. They are not even Danish names.
Factual error: When Paige goes to Denmark after the prince, she gets stuck in traffic because of a parade. Every single person in the parade is in a wrong uniform: the police officers on motorbikes, the police keeping back the onlookers, the military marching band, and the Hussars. (01:01:50 - 01:04:20)
Factual error: Denmark hasn't had a coronation since that of Christian VII in 1840. Edward, were he to become king, would be proclaimed the new monarch without such a ceremony.