Burgruine Aggstein is the remnant of a castle on the right bank of the Danube, north of Melk. According to archaeological excavations of the foundations of the castle it has been inferred that the castle was built in the early part of the 12th century. The castle was built by Manegold III Aggsbach Getbeen of the Kuenringer family descent and his son Aggstein Manegold IV inherited it as a fiefdom of Bavaria. They started living in the castle from 1180 onwards. Its notoriety was due to the 'robber barons' of Schloss Schonbuhel and Burg Agstein' who imprisoned their rivals for ransom and tied them to a rock ledge all the time threatening to kill them by throwing them into the gorge. In 1181, it came into the possession of the Kuenringer Aggsbach-Gansbach. The castle was besieged during the revolt of the Austrian nobility against Duke Albrecht I in 1295/96. Kuenringer Leutold occupied the castle from 1348 to 1355 and then it fell into disrepair.
In 1429, Duke Albrecht V pledged to rebuild the ruined castle because of its strategical point on the Danube. The purpose was to collect taxes from passing boats. In 1438, he built a riverbank toll house to regulate shipping on the Danube and used it as a front to accumulate wealth by robbery from ships. Later, another dishonest baron, Georg von Stain, occupied the castle but in 1476 he was caught and expelled and was forced to surrender the castle. Duke Leopold III took over the castle in 1477. It was occupied with tenants and carers in order to stop the looting which had taken place on the river in previous decades.
In 1529, the castle was burned down by a group of Turks during the first Turkish siege of Vienna. It was rebuilt and provided with loopholes for defence with the help of artillery. In 1606, Anna Baroness acquired the castle, but after her death, the castle was neglected. In 1685, the castle became the property of Count Ernst Rüdiger von Starhemberg. Then in 1819, one of his descendants, Ludwig Josef Gregor von Starhemberg, sold the castle to Count Franz von Beroldingen who renovated the castle in the 19th century. The Beroldingen family owned the castle until 1930 when the estate and the ruins of Schönbühel Aggstein were sold to Count Oswald von Seilern Aspang.
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.