There has been a wooden church in Källa since the 11th century. After it was destroyed by fire, and with increasing attacks from Baltic invaders, a new church of stone - with the aspect of a fortress - was constructed in stages was built in the 13th century. The two-storied construction, dedicated to St. Olav, was very unusual and made for defensive purposes.
The Källa Church fell into disrepair when a new church was built here in the nineteenth century, but has now been taken into the care of the National Heritage Board and is a major tourist attraction. The most valuable of the old Källa Kyrka's furnishings, including the 15th-century triptych carving and the pulpit from 1600, were moved to the new church.
In the churchyard many of the huge old flat gravestones date from the 1600's and 1700's. Older graves have been discovered from the 11th and 12th centuries.
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.