In ancient Russia, Christianity arose long before it received the status of an official religion. However, at that time it was spread too weakly and, of course, could not compete with paganism.
Along with this, the religion of idolatry perceived the influence of other faiths.
Preconditions for the emergence of Christianity began to take shape during the development of trade with Greece. Varangian warriors and merchants, who often went to Constantinople, transmitted the new teachings to the Slavs.
A lot of Christians were in the squad of the Russian Prince Igor, his wife, St. Olga, was also a Christian. Gradually, a new teaching began to spread. Thus, the emergence of Christianity in Russia is closely connected with the first Varangian princes.
Paganism was considered a very unprogressive form of worship in the conditions of the early feudal Russian state. In this regard, Vladimir (the Russian prince) took measures to ensure some correspondence between the political system and religion of the country. Thus, paganism was reformed.
However, such transformations were not enough in the conditions of the early feudal state, requiring the establishment of a monotheistic religion, which would be associated with the power of the Grand Duke.
At that time, three such religions were known in the Kiev state: Judaism, Islam and Christianity. In these conditions, Vladimir had to choose a religion. The closest, of course, was Christianity. However, the difficulty was in choosing the direction. There was eastern and western Christianity. Prince Vladimir resolved this issue under conditions of quite tangible diplomatic influence on the part of Constantinople and Rome.
In all respects, it was more profitable to cooperate with Constantinople (Byzantium). This was largely due to long-established political and economic relations. As you know, the interaction of Kiev and Byzantium continued for centuries, while communication with Rome was rather weak. Thus, the emergence of Christianity as an official religion is associated with Byzantine influence.
However, it should be noted that not immediately the entire population of the Kiev state became Orthodox. At that time, the emergence of Christianity was associated with some violence against the population. As a result, several contradictory and heterogeneous religions formed in the state. All these movements impeded the process of formal Christianization of the local population in many areas of the country. Thus, the emergence of Christianity did not accelerate the elimination of paganism as a religion. On the contrary, idolatry has existed for some centuries.
From the moment Christianity became official religion, the church began to introduce measures to strengthen and develop the organizational system.
The church head was the Kiev metropolitan. Church affairs in major cities were handled by bishops. They controlled large areas - dioceses. At first there were five of these areas, then they became about fifteen.
The emergence of Christianity in the Kiev state did not provoke political subordination to Constantinople. Byzantium did not have full power in the religious sphere either. However, until the 13th century, bishops and metropolitans were, as a rule, Greeks. But they depended completely on the prince of Kiev. Moreover, each prince, within his domain, sought to have his own bishop in the capital.
At first, the church was on princely maintenance. Subsequently, in connection with the expansion of the organizational structure, other sources of income appeared.
Developing and relying on material wealth, the church received a great influence not only on the life of the population, but also on the political and economic life of the country.