https://en.m.wikipedia.org/wiki/Rus%27_people
The Rus', also known as Russes, 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.
Map showing the major Varangian trade routes: the Volga trade route (in red) and the trade route from the Varangians to the Greeks (in purple). Sufficiently controlling strongholds, market places and portages along the routes was necessary for the Scandinavian raiders and traders.
The two original centres of the Rus' were
Ladoga (
Aldeigja), founded in the mid-8th century, and
Rurikovo Gorodische (
Holmr), founded in the mid-9th century. The two settlements were situated at opposite ends of the Volkhov River, between Lake Ilmen and Lake Ladoga, and the Norsemen likely called this territory
Gardar. From there, the name of the Rus' was transferred to the Middle Dnieper, and the Rus' then moved eastward to where the Finnic tribes lived and southward to where the Slavs lived.
The name
Garðaríki was applied to the newly formed state of Kievan Rus', and the ruling Norsemen along with local Finnic tribes gradually assimilated into the East Slavic population and came to speak a common 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 Eastern European scholars.
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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. It is either derived more directly from OEN
rōþer (OWN
róðr), which referred to rowing, the fleet levy, etc., or it is derived from this term through
Rōþin, an older name for the Swedish coastal region Roslagen.
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Roslagen
https://en.m.wikipedia.org/wiki/Roslagen
Roslagen is the name of the coastal areas of Uppland province in Sweden, which also constitutes the northern part of the Stockholm archipelago.

Historically, it was the name for all the coastal areas of the Baltic Sea, including the eastern parts of lake Mälaren, belonging to Svealand. The name was first mentioned in the year 1493 as "
Rodzlagen". Before that the area was known as
Roden.
Roden had a
skeppslag (roughly translated: ship district), the coastal equivalent to the inland Hundreds. When the king would issue a call to leidang, the Viking Age equivalent of military conscript service, the
skeppslag in Roden was responsible for raising ships for the leidang navy.
The name comes from the
rodslag, which is an old coastal Uppland word for a rowing crew of warrior oarsmen. Etymologically,
Roden, or
Roslagen, is the source of the Finnish and Estonian names for Sweden:
Ruotsi and
Rootsi.
A person from Roslagen is called a Rospigg which means "inhabitant of Ros". Swedes from the Roslagen area, that is "the people of Ros", gave their name to the Rus' people and thus, via Rurikid dynasty, to the states of Russia and Belarus.
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