Vadstena Castle was originally built by King Gustav I in 1545 as a fortress to protect Stockholm from enemies from the south. The fortress consisted of three smaller stone buildings facing the lake, Vättern, three 31 meter wide ramparts, a courtyard, a moat and four circular cannons turrets. The original ramparts were torn down in the 19th century and the present ramparts were inaugurated in 1999. The stone buildings later formed the ground floor of the castle.
On August 22, 1552, King Gustav I married his third wife, Catherine Stenbock, in Vadstena. One of the castle banqueting halls is called The Wedding Hall, although its construction wasn't finished in time for the wedding. The reconstruction from fortress into a castle began in the 1550s, when prince Magnus became Duke of Östergötland. Duke Magnus had a mental illness and was the only son of Gustav I who didn't become king of Sweden. Magnus died in 1595 and is buried in the nearby Abbey Church.
In 1620 the castle construction was completed and all the kings of the House of Vasa up till then had led the construction. Since 1620, the castle has been very well preserved, and is one of Sweden's best examples of Renaissance architecture. Vadstena Castle was a royal palace until 1716, when the royal family lost interest in it; after which it became a storage for grain.
Since 1899, the castle has housed the Provincial Archives and today visitors can also find a Castle Museum with 16th and 17th century furniture, portraits and paintings. During summers the courtyard plays host to many concerts; both classical and pop music.
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.