From 990 AD, Château de Castelnou served as the administrative and military capital of the Viscount of Vallespir. Its irregular pentagonal plan follows the rocky outcrop on which it was built, this elevated position providing defence against enemy attacks.
The castle was taken by the troops of James II of Majorca en 1286, and again in 1483. Largely demolished in 1559, it was no longer restored or inhabited and deteriorated throughout the 17th and 18th centuries. At the time of the French Revolution it became the property of the commune. It was sold to Viscount Satgé in 1875 and, by 1900, had become again an elegant and habitable fortress. It was acquired in 1946 by Charles-Emmanuel Brousse who was married to Amy Elizabeth Thorpe, a famed American spy. Having been ravaged by a terrible fire, in 1987 it was sold and has since been restored.
References:Bomarsund fortress and garrison was built in 1832-1854 by Russian Empire to defence Åland Islands against enemies. British and French fleet attacked against it during the Crimean War in 1854. After a week of fighting the British stormed the remaining fort. Anglo-French forces destroyed it totally after battle. In the Treaty of Paris 1856, the entire Åland Islands were demilitarized, which is a status that has been preserved until this day.
Nowadays there are some ruins left and fortress area is open for visitors.