Karlštejn castle has an unique position among Czech castles. It was founded in 1348 by the Czech King and Holy Roman Emperor Charles IV as a place for safekeeping of royal treasures, especially Charles' collection of holy relics and the coronation jewels of the Roman Empire. The first documented stay of Charles IV. in the castle was in 1355 when he came to supervise the building works as well as the decoration of interiors, particularly of the castle chapels. The construction of the castle was finished in 1365 by the consecration of the Chapel of the Holy Cross situated in the Great tower.