The Royal Danish Collections were established at Rosenborg Castle in 1833, and opened to the public in 1838, as one of the first public museums in Copenhagen. The museum''s mission has always been to show a part of Danish history - which was synonymous with the history of the royal family at the time the museum was established. The opening of the museum marked an important break with the exhibition principles that had been accepted up to that point. In the first place, the exhibition was arranged in chronological order. In the second place, the museum created something of a sensation by choosing to exhibit contemporary items, rather than only displaying objects from the past. These principles are still maintained today, thus permitting an exhibition to be opened at Amalienborg Palace in 1994, which was updated in 1999 to include items from the reign of King Frederik IX. The exhibitions are presented as interiors, furnished with items linked to the various Danish kings and queens from Christian IV to Frederik IX. At Rosenborg Castle, the settings in which the exhibitions are presented consist primarily of a number of original seventeenth and eighteenth-century interiors, supplemented with nineteenth-century museum display elements, while Amalienborg Palace involves entire furnishings transferred to the museum, primarily the private studies of the Danish monarchs.These exhibitions feature portraits, furniture, hand-crafted wooden items, semiprecious stones, glass, amber, porcelain, various natural materials and items of silver and gold. There is also a large collection of costumes. Rosenborg Castle was built during the period 1606-24 by King Christian IV, as his '"summer residence in the country.'" This was the king''s favourite castle, and he often resided there when he was officially in Copenhagen. It was also the place where Christian IV died in 1648. The castle was used by his successors, and a limited renovation project was carried out around the year 1710. The castle has not been used as a permanent residence, however, since around 1725, but has instead served as a storage facility and box room. The castle has housed a museum since 1833. Rosenborg Castle was built during the Dutch-influenced Renaissance period, in a style that has since come to be called the Christian IV style in Denmark. The red brickwork, decorated with bands and other architectural details in stone, are typical of this style.