Montebourg Abbey was probably established by William the Conqueror after the invasion to England (1066). The exact date is unknown, but it was before William's death in 1087. The abbey got lot of donations from the Dukes of Normandy and Kings of England until the 1180s. It had a large land property even in the southern England and the abbey grew up quickly in the 12th century.
The abbey suffered damages in the Hundred Years' War, but it was renovated in the mid-15th century. In 1562 Huguenots looted the abbey during the Frencg Wars of Religion. The first school in Montebourg was established in 1585 and in the 18th century it was used as Catholic poor house and rest home. But soon after the Great Revolution caused the decline of Montebourg Abbey. It was reduced to the state and monastic buildings were partially demolished. In 1842, the Vicar General of Coutances acquired what was by then only an enclosure of ruins, and set it up for the Brothers of Mercy, which he had just formed in order to promote Catholic education in the countryside. From there, the brothers have continued their work.
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.