To be privately owned
Breitenau Castle

Breitenau Castle, now known as Breitenau Manor, is an estate in Pennewang-Breitenau. Its origins date back to the 10th century, and it was associated with St. Peter's Abbey for centuries.
History+
The first documented mention of Breitenau dates back to 987, when Archbishop Friedrich of Salzburg transferred the properties to St. Peter's Abbey as part of a property division. Through further donations, the Breitenau office grew. Despite repeated attempts by noble families such as the Jörger von Tollett in the 16th century and Lambach Abbey in the 17th century to acquire the dominion, Breitenau remained in the possession of St. Peter's Abbey until the abolition of manorialism between 1848 and 1850. Even today, the manor and its associated lands are owned by the abbey. The exact relationship between a presumed castle and Breitenau Manor is not fully clarified, as individuals mentioned, such as Ulrich der Salmansleyter (1411) or Jörg der Treytelkover (1452), were also listed as administrators of the St. Peter's estate. The list of administrators of the Breitenau dominion has been continuously documented since the 12th century.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:Gut_Breitenau.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: 48.1273, 13.8681