Radzyn Chelminski was the seat of the Teutonic Knights' Commandry. The castle is one of the oldest castles built by the Teutonic Knights, built in the 13th century. In 1446 the castle went into Polish control, in 1628 during wars with the Swedes the castle was partially devastated, slowly turning into a ruin.
Currently you are still able to see the tower - damaged by artillery fire. In 1780 Prussian authorities ordered to deconstruct whatever is let of the castle. Bricks from the three wings of the castle were used to build houses for the nearby community. The castle's deconstruction was stopped towards the end of the 19th century.
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.