Located in the eastern Pyrenees at an altitude of 1600 metres, the stronghold of Mont-Louis was built from scratch by Vauban on granite terrain and is perfectly adapted to the geography of the site. Work started in 1679 and was completed in two years. The fortified ensemble was added as a complement to Villefranche-de-Conflent in securing the route from the Pyrenees.
This ensemble consists of two square structures, in tiers on the slope: a citadel with orillon bastions and demi-lunes (ravelins) and a new town enclosed in the enceinte. Although it is rare, all the watch towers and drawbridge gates as well as both churches and wells have been preserved intact since the 17th century. The citadel is still used for military purposes today.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.