Friedrich Castle is located on three islands, originally the private estate of the Danish nobleman Helov Troller. In 1560, King Frederick II took the fancy of him and exchanged it with Troller in a forest monastery in Nestorius, south of the island of Siam. Since then, the estate has been renamed as Frederick Castle. After King Kristin IV ascended to power, he built palaces, palaces, churches throughout the country, and also greatly expanded Frederick Fort, making it the first scale, becoming a palace for kings and royals.