The first known owner of Sjöö castle was Peter Laurensson, mentioned in 1409. In 1541 the castle was bought by Jacob Vestgöte Sjöö and named after him. The present castle was built during the ownership of Johan Gabriel Stenbock. The castle was designed by Nicodemus Tessin the Elder and Mathias Spieler. The castle with its park is considered one of the most beautiful castles in Sweden with its perfect and harmonious proportions. In 1813 Sjöö castle was sold to Johan Gustav Baner, and it's still owned by the family Baner.
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.