Finished in 1259, Stolzenfels was used to protect the toll station at the Rhine, where the ships, back then were the main transport for goods, had to stop and pay toll. Over the years it was extended several times, occupied by French and Swedish troops in the Thirty Years' War and finally, in 1689, destroyed by the French during the Nine Years' War.
For 150 years the ruins decayed, until in 1815 they were given as a present to Frederick William IV of Prussia by the city of Koblenz. Following the romantic traditions, the prince started to completely rebuild the castle after 1826 as a summer residence. Supported by famous neoclassic architect Karl Friedrich Schinkel, the castle was completely remodeled in the then fashionable neo-Gothic style, aiming to create a romantic place representing the idea of medieval knighthood - the architects even created a tournament site.
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.