The oldest parts of Guldrupe church is the nave, dating from the late 12th century. Oak planks decorated with dragons have however been found on the site, and indicate that there may have existed an earlier, wooden church on the spot. The tower dates from the early 13th century, and from the end of the same century dates the un-proportionally large choir and sacristy. The choir replaced an earlier, smaller choir, but plans to replace also the nave were never carried out. The church has not been substantially altered since the Middle Ages. The windows date from 1865 and the church was renovated in 1964-65.
The church is built of limestone. The nave and tower are Romanesque in style, while the somewhat later and larger choir is Gothic. The pyramidal tower spire is unusual in that its construction is largely original.
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.