Illingen Castle was documented first time in 1359 when it was owned by Dietrich V. von Kerpen (this is why castle is also called Kerpen Castle). In the16th century it was moved to the hands of Nassau-Saarbrücken counts, who owned Illigen until French Revolution. Illingen castle was badly damaged in the Thirty Years' War and rebuilt later.
The castle started to decay after 1825 and was used as a quarry. The tower was restored in 1951 and today there is a restaurant.
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.