Albrechtsberg Castle was probably built in the 12th century and was documented first time in 1230. It belonged to Protestant Neidegger family from 1377 until 1527 and was badly damaged in Hussite Wars. Knight Erasmus von Peuckham converted it into a Renaissance style residence in the 16th century. The castle was again damaged during the Thirty Years' War.
The towering, irregular structure largely dates from the second half of the 16th century. It is characterized by its high, crenellated ring wall, which features prominent watch and defense towers with numerous keyhole slits. The three-story, multi-winged complex includes three courtyards, a southern entrance through a round-arched portal marked '1675' in the gable field, and a main gate in the northeast with a machicolation. One courtyard contains a cross-vaulted arcade on squat columns. Additional features include a smoke kitchen with a pyramid chimney, cross-vaulted rooms, a wooden ceiling marked '1604,' and an 18th-century granary with a hipped roof. The castle chapel houses the burial site of the Neidegger family.
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.