To be privately owned
Pürnstein Castle

In the Mühlviertel region near Neufelden, Pürnstein Castle, one of the best-preserved fortifications in Upper Austria, stands high above the Große Mühl river. Its history dates back to the early 11th century.
History+
A fortification at this site was first mentioned in 1010 as an episcopal castle of the Passau bishops. In 1170, Alram de birchenstaine appeared as the first documented owner, a ministerialis of the Blankenberg family. In the 13th century, the castle came into the possession of the Prince-Bishopric of Passau, which had it administered by burgraves but often had to pledge it due to financial difficulties. Between 1309 and 1311, Jakob de Strachner was named as a feudal tenant. After several changes of ownership, including Hans von Kapellen and Dietrich von Harrach, the castle passed to Ulrich III. von Tannberg in 1344. From 1455, the Starhemberg family expanded the complex into what is now known as the Upper or New Castle, demolishing much of the original structure and erecting a new fortress. The castle chapel was consecrated on July 20, 1449. In 1493, Balthasar von Starhemberg bequeathed the castle to his cousin Gregor. In 1526, Pürnstein served as a refuge from the Turks.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:P%C3%BCrnstein_1_Gesamt.jpg
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 48.5019, 14.0125