Oleg of Novgorod moved the capital of the Rus people to Kiev, founding the Kievan Rus, a powerful federation of East Slavic tribes. A skilled warrior, Oleg pursued successful campaigns against the Khazars and the Byzantines.
Accounts of Oleg's life are shrouded in legend, but historians agree that he was a kinsman of Rurik, a Viking prince who founded the Rurik Dynasty. After Rurik's death in 879 A.D., power passed to Oleg, who headed down the Dneiper River from Novgorod with his army to conquer the cities of Smolensk and Kiev in 882. He saw the benefits of Kiev's strategic location, so he made the city his capital.
He united the Finnish and Slavic tribes of Eastern Europe under his control, creating a powerful political force. Oleg then moved against the Khazars, freeing some Slavic tribes from their domination. Finally, he attacked the great Byzantine Empire, raiding the capital of Constantinople in 907 A.D. and extracting tribute from the Byzantine government. He also secured a trade agreement with the Byzantines which led to a long and advantageous relationship between the two polities. Oleg died around 912 A.D., though historians debate the manner of his death and the location of his final resting place.