The Val Duchesse/Hertoginnedal estate dates back to the 13th century, when a Dominican priory was established there. Since then, it has undergone numerous changes. When Baron Charles Dietrich acquired it in 1903, only one wing of the castle, part of the surrounding wall and a few farm buildings were still standing. Dietrich commissioned architect Albert Roosenboom to restore and extend the complex from 1915 onwards. The current priory, a semicircular brick building, is the result of the reconstruction of the agricultural outbuildings. Some distance away stood the Orangery, overlooking the park. With a terrace in front, enclosed by a double staircase at either end, the neoclassical pavilion consisted of a single, mezzanine level and a succession of seven bays. It was used as a greenhouse to house the orange trees during the winter. The castle itself is a mix of styles, the oldest part being the Louis XV-style south wing, which is believed to date from 1780. Inside, the well-preserved rooms reflect the interior decor in vogue at different times, including the office in Flemish neo-Renaissance style, the Louis XVI-style Golden Room, the Gothic Room and the Delft Room, whose walls are lined with ceramic tiles from the Dutch city of that name. Charles Dietrich bequeathed the estate to the Belgian Royal Trust in 1930, since when it has provided a setting for political meetings. (Listed 05/12/2002 and 23/10/2003)