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 ancient Argos Theater was built in 320 BC. and is located in Argos, Greece against Larissa Hill. Nearby from this site is Agora, Roman Odeon, and the Baths of Argos. The theater is one of the largest architectural developments in Greece and was renovated in ca 120 AD.
The Hellenistic theater at Argos is cut into the hillside of the Larisa, with 90 steps up a steep incline, forming a narrow rectilinear cavea. Among the largest theaters in Greece, it held about 20,000 spectators and is divided by two landings into three horizontal sections. Staircases further divide the cavea into four cunei, corresponding to the tribes of Argos A high wall was erected to prevent unauthorized access into the theatron and may have helped the acoustics, but it is said the sound quality is still very good today.
Around 120 CE, both theaters were renovated in the Roman style.