Cherven was one of the Second Bulgarian Empire's primary military, administrative, economic and cultural centres between the 12th and the 14th century. The town was a successor to an earlier Byzantine fortress of the 6th century, but the area has been inhabited since the arrival of the Thracians. Cherven was first mentioned in the 11th century in an Old Bulgarian apocryphal chronicle. It gained importance after 1235, when it became the seat of the medieval Bulgarian Orthodox Bishopric of Cherven.
During the second half of the 14th century, the stronghold's area exceeded 1 square kilometre and had intensive urban development, including a fortified inner city on vast rock ground in one of the Cherni Lom river's bends, and an outer city at the foot of the rocks and on the neighbouring hills. The town had a complex fortification system and was completely built up. Cherven grew to become a centre of craftsmanship in the 14th century, with iron extraction, ironworking, goldsmithing, construction and arts being well developed. The town was an important junction of roads from the Danube to the country's interior, which also made the town a key centre of trade.
Cherven was conquered by the Ottoman Turks in 1388 during the Bulgarian-Ottoman Wars, initially retaining its administrative functions but later declining in importance.
A large feudal palace with fortified walls reaching up to 3 metres wide, two well-preserved underground water supply passages, 13 churches, administrative and residential buildings, workshops and streets have been excavated. The three-storey tower, 12 metres high, from the 14th century has also been fully preserved and was even used as a model for the reconstruction of Baldwin's Tower in Tsarevets, Veliko Tarnovo, in 1930. The site has been a national archaeological reserve since 1965 and is a popular tourist attraction.
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.