In the 10th century, Russia embraced an Orthodox version of Christianity and the Byzantine model of government, which set it apart from Germano-Roman Western Europe.
An amazing blunder. It is commonly accepted that the Rus’ of Kiev and Novgorod, both before and after the Baptism, was a decentralized association of principalities governed by princes whose power was checked by their military retinue, local boyars, and the veche (a popular assembly) — the opposite of the Byzantine model. It is only with the ascent of Moscow, its annexation of ancient principalities and the expulsion of the Mongol Horde that a model of government resembling Byzantium emerges in North-Eastern Russia. That would be the second half of the 15th century the earliest, five centuries after the Baptism.