St. Mary's Church was built from 1247–1343 and is one of the most distinct Gothic buildings in Swabia. Between the 1520s and 1540s the church was a center of the Swabian reformer Matthäus Alber, who spread the teachings of Martin Luther to Reutlingen and surrounding areas. The church was heavily damaged during a fire in 1726. From 1893-1901 it was rebuilt in Neo-Gothic style. On the 71-meter high west tower shines a gilded angel from 1343.
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.