Kost Castle is is privately owned by Kinský dal Borgo noble family. It was first proposed by Beneš von Wartenberg in 1349 as a possible construction site and was completed by his son Peter von Wartenberg. It retains most of the original features and is overall very well preserved and maintained.
The castle is known for its so-called 'White tower'. In about 1414 the family of Zajíc von Hasenburg moved there; later the family of Schellenberg (1497 - 1524), Lobkowicz (till 1576) and others; in this time some more buildings were built near the castle and joined to it.
Unlike most other castles in Bohemia, it does not lie on a hill, but on a spit between two brooks. Another peculiarity is the tower, which has a trapezoid-like ground-plan. The trapezoidal tower has the corners facing the areas of most likely catapult attacks. This is to make the missiles glance off the tower walls instead of hitting it headon thereby minimizing the damage.
The castle is open to the public and hosts events and exhibitions.
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.