In OTL Russia only really got going as a trade route from the baltic to the black and Caspain seas, and because of it's many intersecting rivers, it made trade useful, this allowed for greater cultural influence to the native slavic peoples by Byzantine, Viking, and (to a lesser extant) Muslim peoples. What if this happens much earlier? Preroman conquest the greeks somehow get it in there heads to explore and trade along the russian rivers. What happens?