The Citadel Namur is a fortress dates originally from the Roman era, but has been rebuilt several times. Its current form was designed by Menno van Coehoorn, and improved upon by Vauban after the siege of 1692. It has been classified as a Wallonia's Major Heritage site.
The original citadel dates to 937. It achieved its present extent between 1631 and 1675, when the city was under Dutch control. This section was called Terra Nova to distinguish it from the smaller fort built adjacent in 1542 and ensuing years. A variety of subsidiary positions were built in the 18th century. It was disestablished as a military post in 1891, superseded by a new ring of forts around Namur that were calculated to prevent the city from being attacked with artillery. This ring became the Fortified Position of Namur in the 1930s.
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.