The Île Sainte-Marguerite island is most famous for its fortress prison (the Fort Royal), in which the so-called Man in the Iron Mask was held in the 17th century.
The island is first known to have been inhabited during Roman times, when it was known by the name Lero. In 1612, ownership of the island passed from the monks of Saint-Honorat to Claude de Lorraine, Duke of Chevreuse. Shortly after, construction of a fort on the island (to become the Fort Royal) began. In 1635, the island was captured by the Spanish and recaptured by the French two years later.
Towards the end of the 17th century, the Fort Royal became home to a barracks and state prison. During the 18th century, the present-day village of Sainte-Marguerite developed, thriving on the spending power of the soldiers stationed on the island.
The Fort Royal was home to a number of famous prisoners until its closure in the 20th century. As well as the Man in the Iron Mask, a mysterious prisoner whose identity remains unknown, Abd al-Qadir al-Jaza'iri (an Algerian rebel leader), Marquis Jouffroy d’Abbans (inventor of the steamboat) and Marshal Bazaine (the only successful escapee from the island) have all spent time there.
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.