The Cathedral of the Twelve Apostles forms part of the same building as the Patriarch's Palace. Although building began in 1640, the whole ensemble is primarily associated with Patriarch Nikon (1652 - 1658), whose tenure as head of the Russian Church was marked by the schism that separated the Old Believers from the official church, and by ongoing conflict with Tsar Aleksei.
The site of the Palace dates back further, however. Since the early 14th Century this plot of land had been the Metropolitan's, and then the Patriarch's estate. The Cathedral forms the grand entrance to the luxurious Palace, and was built on Nikon's own initiative - the atrium of the church led directly to the Patriarch's stone cell. The design of the Cathedral is based on the old churches of Vladimir and Suzdal, with four supporting columns, five cupolas, and a high, two-tiered porch on the northern face. Although the smooth, somewhat austere exterior of the building is unobtrusive, the original interiors of the Palace were reportedly astonishingly lavish, rivalling the Tsar's own Terem Palace in luxury and wealth.
The five-tier iconostasis in the Cathedral was transferred here from the Ascension Monastery, which was destroyed in the 1920s. The Cathedral also contains images of Saints Peter and Paul drawn in the 12th Century, which were a gift to Peter the Great from the papacy. The Cathedral was closed down in 1918, and the ground floor of the Palace and Cathedral now houses the Museum of 17th Century Life and Applied Art, which contains a number of icons from various of the Kremlin cathedrals, as well as furniture and ecclesiastical costumes from the time.
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.