Büren Castle was built in 1621-24 as the residence of the Bernese Landvogt over the area. It was built on the site of four farm houses. Between 1624 and the 1798 French invasion a total of 77 Landvogts lived in the castle. Some of the bullet scars from the troops that invaded in 1798 are still visible on the castle walls. Today the castle is home to the municipal administration and government offices. In 2003 the 17th century murals and other art were restored to their original appearance.
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.