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:The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.