The Kehlburg castle was built probably in 933 By the bishop Altwin of Brixen at the hillside over Gais. The most important owners later were the noble family Rost zu Aufhofen, which had the castle in possession for nearly three centuries.
After the fire in 1944 where the castle was nearly completely destroyed, the chapel of the holy Erasmus was rebuild so this was used for many years as a much visited pilgrimage. Unfortunately the castle and the chapel is damaged by vandalism.
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.