Kuusisto Castle was a medieval episcopal castle built in the beginning of the 14th century. It was the main residence of Finnish Catholic bishops until 1522, when the last bishop Arvid Kurki drowned when fleeing from Danish soldiers.
Kuusisto heyday was in the in the beginning of the 15th century, when bishop Maunu Tawast spent lot of time and money to enlarge the castle. The castle was ordered to be demolished during the Protestant Reformation in 1528 by the king Gustav I of Sweden. Stones of the castle were later used in renovations of Turku and Kastelholma castles.
Excavation and reconstruction work on the remaining ruins began in 1891.
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.