The oldest part of the present Bossenstein Castle is the square keep, probably built before the 14th century by a Joannes van Busco or Van den Bossche. Not much later it went to the Van Berchem family. They are supposed to have made some major alterations to the castle. They sold it in 1544 to Guilelmus van der Rijt, who was a member of the city council of nearby Antwerp. In the deed of sale the castle was described as an impressive estate, with a lot of outbuildings. Of these outbuildings nothing survives.
In 1655 it was sold again, this time to Willem van Halmale. He rebuilt the castle into a beautiful residence, which was still fortified. During the 18th century the castle changed hands several times between several noble families. Between 1798 and 1843 the castle was used by religious institutions. In 1906 the castle underwent restoration works, saving it from slow decay.
At present the castle is surrounded by the grounds of an 18-hole golf and polo club. The terrain of this club is probably not freely accessible. There is however a long distance walking path leading through the golf course which is. As far as I know the castle itself can not be visited.
References:The Château de Chantilly comprises two attached buildings: the Petit Château built around 1560 for Anne de Montmorency, and the Grand Château, which was destroyed during the French Revolution and rebuilt in the 1870s. Owned by the Institut de France, the château houses the Musée Condé. It is one of the finest art galleries in France and is open to the public.
The estate"s connection with the Montmorency family began in 1484. The first mansion (now replaced by the Grand Château) was built in 1528–1531 for the Constable Anne de Montmorency by Pierre Chambiges. The Petit Château was also built for him, around 1560, probably by Jean Bullant. In 1632, after the death of Henri II, it passed to the Grand Condé who inherited it through his mother, Charlotte Marguerite de Montmorency.
Several interesting pieces of history are associated with the château during the 17th century.