Nyköping Castle is a medieval castle from the Birger Jarl era, partly in ruins. The castle is mostly known for the ghastly Nyköping Banquet which took place here in 1317. The construction of the castle began in the end of the 12th century, when it began as a fortification. It is thought Birger Jarl expanded the building to a larger castle. During the reign of Albert of Sweden the castle was held as a fief by the German knight Raven van Barnekow, who made important improvements on the building, and later by Bo Jonsson Grip. Further reconstructions and expansions were done during the late Middle Ages. Gustav Vasa strengthened the castle further for defensive purposes and a round gun tower from that time remains today.
The medieval castle was rebuilt in the end of the 16th century by Duke Charles (later Charles IX of Sweden) into a renaissance palace. The palace burned down with the rest of the city in 1665. It wasn't reerected; in fact some of its bricks were used in the construction of Stockholm Palace. However, parts of the castle were sound enough to be used as county residence until the 1760s.
Parts of the castle were refurbished in the 20th century. Kungstornet (the King's Tower) and Gamla residenset (the Old Residence) currently house the permanent exhibits of Sörmlands museum (the Museum of Södermanland). A restaurant is located in the banquet hall and Drottningkällaren (the Queen's Cellar).
References:The Château de Chantilly comprises two attached buildings: the Petit Château built around 1560 for Anne de Montmorency, and the Grand Château, which was destroyed during the French Revolution and rebuilt in the 1870s. Owned by the Institut de France, the château houses the Musée Condé. It is one of the finest art galleries in France and is open to the public.
The estate"s connection with the Montmorency family began in 1484. The first mansion (now replaced by the Grand Château) was built in 1528–1531 for the Constable Anne de Montmorency by Pierre Chambiges. The Petit Château was also built for him, around 1560, probably by Jean Bullant. In 1632, after the death of Henri II, it passed to the Grand Condé who inherited it through his mother, Charlotte Marguerite de Montmorency.
Several interesting pieces of history are associated with the château during the 17th century.