Uniejów Castle castle was built between 1360-1365 on the site of a former wooden fortress, destroyed after a raid by the Teutonic Knights in 1331. The initiator of the construction of the castle was Gniezno's Archbishop Jarosław Bogoria Skotnicki, one of the closest associates to Casimir III the Great.
The building was greatly expanded and modernised between 1525-1534, when after a fire most of the castle's Gothic characteristics had gone. The stronghold had ended's its militaristic significance in the seventeenth century, when the castle became a residence. In 1836 the castle was taken over by the House of Toll, an Estonian family. In 1848, Aleksander Toll had reconstructed the castle into a Classical architectural style. The castle in Uniejów is a prime example of accretion of architectural styles.
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.