The thing is, the ethnonym "Rus" was used appropriated from your ancestors from mine (the Swedish ones, actually their cousins): here is the original "Rus"
http://upload.wikimedia.org/wikipedia/commons/9/9d/FC-Uppland%2C_Sweden.png
Roslagen refers to the coastal areas here of Svealand, the core of Sweden (he is the King of the Swedes/Svea, Goths (that's my ancestors) and Vandals). Roden means to row and the districts each had to provide and man a ship for the king. From there expeditions were launched across the Baltic, so the name gave rise to the Finnish and Estonian terms for Swedes:Ruotsi and Rootsi (both Finland and Estonia being under Sweden before under Russia). From the Baltic they spread down to the Black Sea.
Their polity got its start in Novgorod, Russia, Slavic and Finnic tribes inviting Rurik . It then spread to the South with its dynasty, the Rurikids, who later conquered and then founded Kiev as the seat of their chief prince (kn'az, from the same Germanic root kuningaz which becomes king in English), Helgi (Slavic Oleg) moving his capital from Novgorod to Kiev. The Rota system keep rotating the princes among the city states, so the Grand Princes of Kiev (like Vladimir and Yaroslav) ruled Russian cities first.