Bilstein castle is located on a spur which falls away steeply on three sides so that the castle's defences only needed to be oriented towards the hill to the northeast. The appearance of the castle is thus dominated by its two round towers, each with a diameter of about eight metres: the Chapel Tower in the northwest and the Hohnekamp Tower in the southeast. The towers are connected by a tunnel under the castle courtyard, above ground is a 20th century archway.
The castle was built between 1202-1225. The Electorate of Cologne conquered it after a siege in 1445. Later it has been used for administrative purposes.
The northwestern wing of the main ward and the central block in the southwest are historical structures. By contrast, the wing in the southeast was built in 1978 to expand the hostel. On the valley side of the central block is a portal terrace (Söller) on which a prominent lime tree is growing.
Today a brick bridge spans the moat between the inner and outer baileys. The moat has been partly filled-in and is about 15 metres wide. The outer bailey comprises three buildings, which are referred to as the gatehouse, timber-framed house and festival hall.
References:Rosenborg Palace was built in the period 1606-34 as Christian IV’s summerhouse just outside the ramparts of Copenhagen. Christian IV was very fond of the palace and often stayed at the castle when he resided in Copenhagen, and it was here that he died in 1648. After his death, the palace passed to his son King Frederik III, who together with his queen, Sophie Amalie, carried out several types of modernisation.
The last king who used the place as a residence was Frederik IV, and around 1720, Rosenborg was abandoned in favor of Frederiksborg Palace.Through the 1700s, considerable art treasures were collected at Rosenborg Castle, among other things items from the estates of deceased royalty and from Christiansborg after the fire there in 1794.
Soon the idea of a museum arose, and that was realised in 1833, which is The Royal Danish Collection’s official year of establishment.