The structure of the present St Mary's Church is thought to originate from the 13th century, although because the churchyard is round in shape, it is likely that there had been an earlier church on the site. Additions and modifications were made during the following centuries. Dating from the pre-Reformation period are the east window, the roof and the rood screen. The bellcote is dated 1688. The church was restored in 1857. the restoration included removal of the west gallery. Encaustic tiles were laid in the sanctuary in 1907.
The floor of the nave is flagged, the chancel has a wood-block floor, and the sanctuary has encaustic tiles. The outstanding feature of the interior is the rood screen which has retained its loft. It is finely carved with Perpendicular features. The font is dated 1665. The rest of the furniture dates from the 19th century. This includes a large, carved, octagonal pulpit, an oak altar, and an octagonal font.
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.