Oleg of Novgorod was a Varangian prince (or konung) who ruled all or part of the Rus’ people during the early 10th century.
He is credited with moving the capital of Rus’ from Novgorod the Great to Kiev and, in doing so, he laid the foundation of the powerful state of Kievan Rus’. He also launched at least one attack on Constantinople, capital of the Byzantine Empire. According to East Slavic chronicles, Oleg was supreme ruler of the Rus’ from 882 to 912. This traditional dating has been challenged by some historians, who point out that it is inconsistent with such other sources as the Schechter Letter, which mentions the activities of certain khagan HLGW of Rus’ as late the 940s, during the reign of Byzantine Emperor Romanus I. The nature of Oleg’s relationship with the Rurikid ruling family of the Rus’, and specifically with his successor Igor of Kiev, is a matter of much controversy among historians.