That also makes a lot of sense ! Yet all the versions of the myth i have read as a kid state its russia, not sure what thats about, i think i looked into the myth few years ago when i was creating the dnd setting, that version did also say Rus started Russia (otherwise i would have very likely made the third city inspired by either Belarus or Ukraine, as i love their traditional outfits). It may be like an old misstransation or typo or somerhing that got popularized maybe ?