https://en.m.wikipedia.org/wiki/Rus%27_people

> The Rus' people (Old East Slavic: Рѹсь; Modern Belarusian, Russian, Rusyn, and Ukrainian: Русь, romanised: Rus'; Old Norse: Garðar; Greek: Ῥῶς, romanised: Rhos) were an ethnic group in early medieval eastern Europe. The scholarly consensus holds that they were originally Norse people, mainly originating from present-day Sweden, settling and ruling along the river-routes between the Baltic and the Black Seas from around the 8th to 11th centuries AD. They formed a state known in modern historiography as Kievan Rus', which was initially a multiethnic society where the ruling Norsemen merged and assimilated with East Slavic, Baltic and Finnic tribes, ending up with Old East Slavic as their common language. The elite of Kievan Rus' was still familiar with Old Norse until their assimilation by the second half of the 11th century,[1] and in rural areas vestiges of Norse culture persisted as late as the 14th and early 15th centuries.[1]