To be privately owned
Pettendorf Castle

Pettendorf Castle, an estate in Bavaria, has a history, evolving from a manor house to a monastery and then to a country residence. It is near Regensburg and is currently privately owned.
History+
The origins of the estate date back to the 11th century. Around 1120, it served as a monastery for about 50 years, adjacent to the then-existing castle. A fire in 1174 almost completely destroyed the building. After its reconstruction, it was used as a parish church. The original manor house, which supplied the castle, remained in the possession of the Wittelsbach rulers even after the second monastery foundation in the 1260s. Following the Peace Treaty of 1505, the manor house passed from the Wittelsbachs to the new rulers of Pfalz-Neuburg, who sold it during the Thirty Years' War.
Source: Wikipedia · Licence: CC BY-SA 4.0
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: 49.0592, 12.0048