Angenstein castle was founded in the middle of the 13th century by the for a strategic outpost between Basel and the Jura area. It was owned by the Counts of Pfirt, but half of it was apparently ceded in 1271 to the Bishop of Basel.
After 1557 the castle was destroyed by fires (1494 and 1517) and turned into a residence. The four-storey residential tower was built, which still characterize the appearance of Angenstein. The chapel was built in 1562 with new residential and commercial buildings. Its most important jewelery were three splendid glass windows, donated by the Bishop.
Thirty Years' War, fires and the poor conditions of the changing owners led to an increasing neglect. At the beginning of the 19th century numerous changes were made. In 1951, the city of Basel bought the Angenstein. In 1984 the castle was burned for the last time. From 1988 to 1991 it was completely renovated.
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.