Castle Loevestein (Slot Loevestein in Dutch) is a medieval castle built by the knight Dirc Loef van Horne (hence "Loef's stein" ((stone)) house) between 1357 and 1397. Until the Second World War Loevestein Castle was part of the Nieuwe Hollandse Waterlinie, the main Dutch defense line that was based on flooding an area of land south and east of the western provinces. Currently the castle is used as a medieval museum and function centre.