Žumberk Castle was probably built during the end of the 13th century, on a hilltop above the village, and was known under the German name Sunenberg. Its walls formed a pentagon and were surrounded by a deep moat, with a service yard was placed next to the castle. Later, a township grew up under the hill.
The first known owner of the castle and neighbouring villages was a robber knight; ownership of the castle changed many times afterwards. At the beginning of the 18th century, the castle was not inhabited, though during 1760–70 a physician lived there. The castle became desolate and was left to be a source of construction material.
During 1926–48 the castle was owned by the Club of Czech Tourists, and its structure was stabilized to prevent further destruction. Today the market town of Žumberk is responsible for its maintenance, and access to the castle is unlimited and free.
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.