The roots of Russia's history began when the East Slavs formed a group in Europe between the 3rd and 8th centuries AD. The Vikings and their descendants founded the first East Slavic state of Kievan Rus' in the 9th century. They adopted Christianity from the Byzantine Empire in 988. This form of Christianity influenced Russian culture greatly. Kievan Rus' eventually broke up and the lands were divided into many small feudal states. The most powerful successor state to Kievan Rus' was the Grand Duchy of Moscow. This area served as the main force in later Russian unification and the fight against the Golden Horde from Asia. Moscow slowly gained control of the regions around it and took over the cultural and political life of Kievan Rus'.