Neuhaus castle dates probably back to the 13th century. It may have been built on the site of earlier 12th century fortified house. The pentagonal tower was added in the 14th century and the castle was rebuilt during the 16th century. The traffic on the Danube has been able to deny with chain from the chain tower, located below the castle. Neuhaus was besieged at least in 1381, 1386 and 1389.
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.