Russian history of science begins with a question: Why did the Kievan Rus’, the medieval Slavs to whom modern Russians look as the origin of their culture, neglect the scientific sources of Byzantium, with which they were in close contact? Some Kievan monks and literati from the ninth to the thirteenth centuries did translate Greek texts from the great libraries of Constantinople. As a result, Byzantine influences prevailed in Kievan culture in liturgy, theology, political ideology, and art. Why was science not one of the objects of attention of the Kievan Rus’? Strikingly, during the Middle Ages the Kievan scholars translated no complete work of ancient Greek science, even though the Byzantine libraries were rich in these sources.