Why were there many literate people among the townspeople of ancient Russia?

One of the main reasons that most of the urban population was taught to read and write was that during the reign of Vladimir the Great and Yaroslav the Wise, a large number of libraries were opened on the territory of Kievan Rus.
Church schools were opened at monasteries and laurels, in which city residents received education.
As a result of the fact that Russia was a trade center between Asia and Europe, traders and merchants needed to know languages, arithmetic and writing, in order to competently conduct business.