In what century did the formation of the Old Russian State take place?

Ancient Russia, as we know it, as a state with its capital in Kiev (hence Kievan Rus), was formed in the 9th century AD. It all began in 862 with the vocation of the Varangian Rurik to rule in the northwestern lands of the future state. From there, his comrades-in-arms and descendants went along the Dnieper, where they captured Smolensk and Kiev, becoming there to rule as from the capital. This was in 882, and the supreme prince was Oleg (Helgi) the Prophet, who was famous for his campaigns against Byzantium and nailed his famous shield to the gates of Constantinople.