To be privately owned
Château de Rochebrune

The Château de Rochebrune, an 11th-century castle complex, is located in the French commune of Étagnac, in the Charente department of the Nouvelle-Aquitaine region. It marks the beginning of the Richard the Lionheart tourist route.
History+
The origins of Château de Rochebrune date back to the time of the first Crusades, when it served as a strategically important fortification at the crossroads of major trade routes. Jourdain I de Chabanais initiated the construction of the first tower before departing for Jerusalem in 1099. The remaining three towers were added a century later. Jourdain I's descendants gradually expanded the complex to its current size. During the Wars of Religion in 1561, the castle fell to Blaise de Monluc, a Catholic rival of the Protestants.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: Hervé Rebours
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: 45.8967, 0.7873