Сведения в старобългарските текстове за миграцията от Тракия към днешна Северна България в края на XII – началото на XIII в. И произходът на имената Красен и Червен, Русенско

At the end of the 12th – the beginning of the 13th century, there was a large-scale population migration from the lands south of Stara Planina to the territory north of it. The reasons for this are the Third and Fourth Crusades and, above all, the policy of the restored Bulgarian state, which sought to increase the population in the sparsely populated parts of the lands between the Danube and Stara Planina. This migration is reflected in Byzantine and Western European written sources and is well traced archaeologically. In the Old bulgarian texts it is weakly reflected, but still explicitly mentioned and complements the data known to us from other sources. They mention the names of two fortresses – Krasen and Cherven in the region of today’s city of Ruse. A fortress and a settlement south of Stara Planina have identical names. It is from this region that the population migrated to the lands north of Stara Planina. This repetition of the names in the two areas regions is hardly a coincidence and is indirect evidence of the migration in question, in which the resettled population transferred the names of their old settlements.