KMC Forums - Need help finding old movie

We have been looking for an old blue movie in color that my Mom saw as a child in the 1950's. The actress in the movie plays a duel role of redheaded twins. One of the twins has a birthmark on her thigh that proves she is the heir to the kingdom. There was sword fighing in the movie. The setting was in Europe during the 17th or 18th century. One of the twins changes from boy clothes to girl clothes in a stable. Their parents are either dead when movie starts or they die in begining. The last scene huge double doors to a castle open and the twins are standing side by side in the doorway. We do not know any of the actors names. This movie has been driving my Mom crazy for a couple of years. She finally has the internet so we have been posting the description of the movie anywhere we can hoping someone will recognize it. Anyone who has family members that would have gone to the movies in the 50's please ask them if they remember this movie. Thank you for any help whatsoever!!!!