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 Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.