The Church of the Exaltation of the Holy Cross is located on the site of an original Gothic church from the 13th century. A vestibule with circular vaulting was preserved from a building constructed in 1458, along with the bottom part of the tower. After a fire in 1635 the church was reconstructed in Baroque style (D. Rossi and D. Orsi) and also from 1746-1755 by J.K. Kosh. The church is used for religious purposes. A large reconstruction of the truss and facade was done by the Municipal Office in 1995.
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.