Garz Slavic fort was an ancient burgwall. The earthworks have an oval shape, are about 200 metres long and 140 metres wide. There is an entrance roughly in the middle of the western side. Towards the lake of Garzer See to the south the ramparts are lower.
The castle was mentioned in 1165 as Borgar Gardz, when there were small-scale skirmishes with Danish warriors in front of the castle. The castle itself does not appear to have come under attack, but gradually fell into ruins afterwards. In 1300, the Prince of Rügen, Vitslav III, built a new castle and a chapel inside the original fort. After his death in 1325, the castle finally fell into disrepair. On the ramparts is now a war memorial to those who fell in the First World War and, in its immediate vicinity, is the Ernst Moritz Arndt Museum, where one can learn more about the history of the place.
The Garz fort is now a protected archaeological site. It ranks, in terms of size and degree of preservation, as one of the most important Slavic strongholds.
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.