The Rus' (Роусь; Belarusian, Russian, Rusyn, and Ukrainian: Русь; Old Norse: Garðar; Greek: Ῥῶς, Rhos) were a people in early medieval eastern Europe. The scholarly consensus holds that they were originally Norsemen, mainly originating from present-day Sweden, who settled and ruled along the river-routes between the Baltic and the Black Seas from around the 8th to 11th centuries AD. In the 9th century, they formed the state of Kievan Rusʹ, where the ruling Norsemen along with local Finnic tribes gradually assimilated into the East Slavic population, with Old East Slavic becoming the common spoken language. Old Norse remained familiar to the elite until their complete assimilation by the second half of the 11th century, and in rural areas, vestiges of Norse culture persisted as late as the 14th and early 15th centuries, particularly in the north.
The history of the Rus is central to 9th through 10th-century state formation, and thus national origins, in eastern Europe. They ultimately gave their name to Russia and Belarus, and they are relevant to the national histories of Russia, Ukraine and Belarus. Because of this importance, there is a set of alternative so-called "Anti-Normanist" views that are largely confined to a minor group of East European scholars.
Names of Rusʹ, Russia and Ruthenia
Note: The þ (thorn letter) represents the voiceless dental fricative /θ/ of th in English thing, whereas the ð (eth letter) represents the voiced dental fricative /ð/ of th in English the. When þ appears in intervocalic position or before a voiced consonant, it is pronounced like ð, so the pronunciation difference between rōþer and róðr is minute.
The name Rusʹ remains not only in names such as Russia and Belarus, but it is also preserved in many place names in the Novgorod and Pskov districts, and it is the origin of the Greek Rōs. Rus is generally considered to be a borrowing from Finnic Ruotsi ("Sweden"). There are two theories behind the origin of Rus/Ruotsi, which are not mutually exclusive.