Bran Castle was built to protect the people of Western Europe from the Mongol invasion of 1241. During this time, most of the area of Transylvania was destroyed, but then it was rebuilt. This also includes Bran Castle.
Peles Castle is found closer to Bucharest than is Bran Castle, so it is better described as a Wallachian Castle. This particular castle was never a part of the Kingdom of Hungary, but it now plays an important tourism role as well.
The Queen is a real person, but she had a memorable personality and was one of the reasons that some people in Transylvania say that the additional land Romania received was in part thanks to her. Peles Castle and Bran Castle, after 1919, were two of her Royal Residences.