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:
Sirmione castle was built near the end of the 12th century as part of a defensive network surrounding Verona. The castle was maintained and extended first as part of the Veronese protection against their rivals in Milan and later under the control of the Venetian inland empire. The massive fortress is totally surrounded by water and has an inner porch which houses a Roman and Medieval lapidary. From the drawbridge, a staircase leads to the walkways above the walls, providing a marvellous view of the harbour that once sheltered the Scaliger fleet. The doors were fitted with a variety of locking systems, including a drawbridge for horses, carriages and pedestrians, a metal grate and, more recently, double hinged doors. Venice conquered Sirmione in 1405, immediately adopting provisions to render the fortress even more secure, fortifying its outer walls and widening the harbour.
Thanks to its strategical geographical location as a border outpost, Sirmione became a crucial defence and control garrison for the ruling nobles, retaining this function until the 16th century, when its role was taken up by Peschiera del Garda.