Rosenborg has a long museum tradition. The core consisted of Christian IV's magnificent collection of riding trappings and parade arms, which were transferred from Frederiksborg Castle in 1658.
Soon after the King's costumes followed together with heirlooms and precious artifacts. During the reign of Christian V the Regalia were transferred from Copenhagen Castle, and during the reign of Frederik IV collections of glass and porcelain arrived, as well as the art collections of the dukes of Holstein, captured from Gottorp Castle.
The Crown Jewels were originally bequeathed for the use of the reigning Queen, because “in this Royal Family there have been so few jewels, and no Crown Jewels at all”, as the benefactress, Queen Sophie Magdalene, wrote in her will in 1746.
In the early 19th century it was suggested that the Royal collections should be opened to the public. The scientist and Court official A.W. Hauch drew up a plan in 1813, innovative in its principle of exhibition. The earlier “theme” rooms were to be replaced with interior exhibitions which followed successive Royal generations chronologically. A walk round the museum would thus be a journey through the history of Denmark from Christian IV to the present day. The Castle was opened to the public in 1838.
After the abolishment of Absolutism in 1849, the Royal castles and palaces became state property. In 1854 Frederik VII agreed with the state that the collection was to become entailed property passed on from king to king.