The fortified complex called 'Citadel' is located on a natural protected hill, located where the main commercial roads intersect in Mezdra. The area of the Iskar River is inhabited since the end of the Stone Age and the beginning of the Copper Age, respectively the second half of the 5th century BC. After these prehistoric populations, who lived in the first known historical period of the area, the ancient Thracians were established here. In the I century the place was conquered by the Roman Empire, and in the seventh century, with the great migration of the peoples of Asia, came here the Slavs, and later the Bulgarians of Asparuh. In the eleventh century, the Byzantine emperor Vasile the Great conquered the northwestern Bulgarian lands. The area was then included in the Ottoman Empire for several centuries.
In 2013, the entire complex is restored and tourist routes are built. You can see the remains of the fortified settlements of different times, the “Sanctuary of the Tour”, a pagan worship center from the 3rd century. In a permanent exhibition hall are exhibited objects and archaeological discoveries from the 5 historical periods and a model of the Roman fortress “Kaleto”, dating from the 2nd-5th century. In a separate building are the handicraft workshops, the information center and the souvenir shop.
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.