Södertuna is a medieval castle located on a small island in Lake Frösjön in Gnesta Municipality, Sweden. It dates to the 14th century and is now a luxury hotel and conference center. The main building is of medieval origin, but was updated during the 17th century and the late 18th century. The last major renovation was in 1892.
It has belonged to members of several families: Sparre, Lovisin, Palmenfelt, Ehrensvard, Wachtmeister, Adelborg, and von Eckermann.
The castle and the park were split off in 1985 by the von Eckermann family. The new owners, together with an additional couple of Norwegian investors, made the palace into a hotel and conference center, which was inaugurated in 1986 by Princess Christina. In 2007 the castle was sold to the Åström family, which also operates Dufweholms Manor Inn and Gripsholm.
References:The Gravensteen is a castle in Ghent originating from the Middle Ages. The name means 'castle of the counts' in Dutch. Arnulf I (918–965), Count of Flanders, was the first to fortify this place, building a medieval bastion on this high sand dune, naturally protected by the river Leie and its marshy banks. This bastion consisted of a central wooden building and several surrounding buildings, also in wood.
In the early 11th century, the wooden building was replaced by a stone residence, consisting of three large halls that made up three storeys, connected by a stone stairwell. The monumental stone staircase, the light openings, the fireplaces built into the walls and the latrines were signs of considerable luxury and comfort in those days. There was probably also a tower.