At the end of the 13th century, Count Floris V ordered the construction of a fortress at an easily defendable location on the shores of the Zuiderzee. Kasteel Radboud was part of a series of fortresses that were intended to keep the Frisians under control. Kasteel Radboud is the only one of these forts still standing. Your visit will take you back to the Middle Ages (partly due to the exhibition). A treasure hunt has been arranged for children.