To be privately owned
Nagelsberg Castle

The Nagelsberg Castle Ruin, once a hilltop castle, is located in Künzelsau-Nagelsberg in the Hohenlohe district, Baden-Württemberg.
History+
The origins of Nagelsberg Castle likely date back to the 13th century. It was first documented in 1282, when it was owned by the Lords of Stein. Just eight years later, in 1290, the last representative of this lineage transferred the castle to Comburg Monastery. From 1330, Nagelsberg belonged to the Diocese of Mainz, which staffed the complex with an official in 1492. In the course of secularization at the beginning of the 19th century, specifically in 1803, the castle was sold to a bourgeois family. An event was the collapse of the keep in 1822, which altered the castle's appearance.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: https://commons.wikimedia.org/wiki/File:Burg_Nagelsberg_Zufahrt.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: 49.2926, 9.6757