Rurik led the Rus' until his death in about 879, bequeathing his kingdom to his kinsman, Prince Oleg, as regent for his young son, Igor. In 880–82, Oleg led a military force south along the Dnieper river, capturing Smolensk and Lyubech before reaching Kyiv, where he deposed and killed Askold and Dir, proclaimed himself prince, and declared Kyiv the "mother of Rus' cities." Oleg set about consolidating his power over the surrounding region and the riverways north to Novgorod, imposing tribute on the East Slav tribes.