Loenersloot Castle Loenersloot Castle: Rijksstraatweg 211, 3634 AL Loenersloot This beautifully restored castle, first mentioned in 1258, was built as a knight’s court town around an extensive keep. It is completely furnished in the 18th-century style and has retained its medieval features such as a moat, ancient tower, thick walls and monastery mops. Inside the castle is a Broadwood table piano, built in 1829, from the Geelvinck Collection.