WWII broke out here at dawn on 1 September 1939, when the German battleship Schleswig-Holstein began shelling the Polish guard post. The garrison, which numbered just 182 men, held out for seven days before surrendering. The site is now a memorial, with some of the ruins left as they were after the bombardment. The surviving Guardhouse No 1 houses a small exhibition related to the event, including a model of the battle labelled in English.
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.