The St. Ursus Cathedral in Solothurn is dedicated to Ursus of Solothurn, who was a 3rd-century Roman Christian venerated as a saint. His his body is located under the cathedral. The first church on the site was built in the Early Middle Ages. St. Ursus of Solothurn was venerated in the city by the 5th century. By 870 there was a college of canons and presumably a collegiate church in Solothurn. A Romanesque church might have existed, but there is no written or archeological evidence to support or refute it.
The first documented record of the Gothic church comes from 1294, while the altars were ordained in 1293 and 1298. It is likely that the twin towers were damaged in the 1356 Basel earthquake damaged, but there is no reliable sources attesting to the damage. It seems likely, since in 1360 the single Wendelstein tower was built above the church and a gothic facade was added to the west face of the church.
The choir was rebuilt in 1544, while the crypt was re-covered. The nave was rebuilt in 1644 and widened. The sacristy was extended in 1664.
By the 18th century the Gothic church was in a poor condition. On 25 March 1762 the Wendelstein tower collapsed forcing the city to begin planning to replace the building. Paolo Antonio Pisoni (1738-1804) took over construction in 1772. On 26 September 1773 the new church was dedicated by the Bishop of Lausanne. The western facade of the cathedral is a monumental white stone neoclassical structure.
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.