I want to know the answer to the following question:
Who declared Kiev "The mother of Rus citis'?
All the background I'm provided with is that "In 880-82, Oleg led a military force south along the Dnieper river, capturing Smolensk and Lyubech before reaching Kiev, where he deposed and killed Askold and Dir, proclaimed himself prince, and declared Kiev the "mother of Rus' cities."". Is that enough to answer the question?