Roman town - fortress „Ratsiaria”, Municipality of Vidin

Ratsiaria is located on a high plateau, situated near the Danube River. Located on 27 km southeastwards of Vidin, east- northeast from the present village Archar, Dimovo municipality, Vidin region, area Kaleto (the Citadel). It was founded during the Roman Empire. At that time there had lived Roman patricians (aristocrats) and the nearby Bononia (today's Vidin) was only a base of small military unit. Roman town-fortress "Ratsiaria" (Latin Colonia Ulpia Ratiaria) was a major city of the Danube limes. Colonia Ulpia Trairana Ratiaria is first mentioned in an inscription of 125 AD the, the earliest well-dated written statement, which mentions its name.

From the late ancient buildings partially excavated, two deserve special attention: in one it is found farm implements, clay lamps, household items, coins from the middle of the sixth century, and the other is part of a monumental building with a mosaic floor and is likely to be Christian basilica. The water for Ratsiaria came from the big spring in area called Zhidovets 6-7 km to the southwest. Traces of water mains are found all along the road between this area and the village. Classifying the known facts over the history and material culture of the Roman town Ulpia Ratsiaria shows its great significance as the richest city center not only in the countryside but also in the whole of the Lower Danube basin.