St Mary's Church (Mariakirken) was the royal chapel and had an important political role, as its provost from 1314 also was Chancellor of Norway. It was built originally in 1050 AD, but rebuilt and expanded several times. Final additions made in the 1300s. In the beginning of the 14th century, it was the third largest church in the country, and in the Middle Ages it was the royal chapel. The church was set on fire by Swedish forces in connection with an attack in 1523. After the Reformation, it was so dilapidated that it could not be repaired and was demolished in 1542.
Excavations were first conducted in 1867 under Nicolay Nicolaysen and later in the 1960s under the leadership of Håkon Christie. Remains of two people, deemed to be King Haakon V (1270-1319) and his Queen consort Euphemia of Rügen, were discovered during excavations of the ruins of the church and reinterred in the Royal Mausoleum in Akershus Castle.
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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.