After the capture of Kiev in 882, Prince Oleg the Prophet firmly established himself in the city, declaring it the new capital and effectively uniting Kiev with Novgorod – he northern and southern centers of settlement of the eastern Slavs.
Together with the further unification under his rule of neighboring tribes such as the Drevlyans, Severians, and Radimichs, this formed a stable core of the emerging state. Therefore, it is often he, rather than Rurik, who is declared the founder of the Old Russian state.
According to V.N. Tatishchev:
Oleg, upon entering Kiev, began to reside in Kiev and said:
«Let this be the mother of all Russian cities.».[1]Tatishchev V.N. Russian History. – book. 2, ch 2.
After the death of Prince Oleg the Seer, his pupil and son of Prince Rurik, Igor, continued the task of unifying Ancient Rus.