Byzantine missionaries created an alphabet for Slavic languages based on a modified Greek script while Rus Viking warriors served as the Byzantine Emperor's elite guard.
Which is an awesome idea and everything, but Russian, the language that developed from what the Rus spoke, sounds a lot more Slavic than it sounds, you know, Swedish.
Religion played an important role in politics, and as the legend goes, in 987, the Rus prince Vladamir I decided it was time to abandon Slavic paganism, and sent emissaries to explore neighboring faiths.