Slangenburg Castle was constructed in the Late Medieval period. In the 17th century the castle became the property of General Frederik Johan van Baer, also known as General Slangenburg, who rebuilt it for residential purposes.
The last private owners were a German family called Passmann, who are buried in a private cemetery next to the moat. After the World War II all German properties were confiscated by the Dutch government, who thus acquired the castle, which, with the surrounding terrain and the buildings within the outer moat, now forms part of the portfolio of the Rijksgebouwendienst ('Royal Buildings Service'), while the surrounding area falls under the care of the Dutch environmental agency, the Staatsbosbeheer.
At present the castle is used as a guesthouse by the nearby Benedictine monastery, St. Willibrord's Abbey, a newly built structure of the 1950s situated on a part of the castle's former estate. The original monastic community, from Oosterhout Abbey, was initially accommodated in the castle itself in the years immediately following the war.
The estate and the monastery chapel are open to the public. The estate, roughly trapezoid in shape, features a system of lanes which is centuries old.
References:The Château de Foix dominates the town of Foix. An important tourist site, it is known as a centre of the Cathars. Built on an older 7th-century fortification, the castle is known from 987. In 1002, it was mentioned in the will of Roger I, Count of Carcassonne, who bequeathed the fortress to his youngest child, Bernard. In effect, the family ruling over the region were installed here which allowed them to control access to the upper Ariège valley and to keep surveillance from this strategic point over the lower land, protected behind impregnable walls.
In 1034, the castle became capital of the County of Foix and played a decisive role in medieval military history. During the two following centuries, the castle was home to Counts with shining personalities who became the soul of the Occitan resistance during the crusade against the Albigensians.