What was the significance of the Orthodox Christian Church in the Byzantine Empire and Russia?

When
Constantine took over the Roman Empire he moved the capital from Rome to Byzantine, which he
renamed after himself Constantinople. When he moved the political seat of the empire this caused
a dramatic shift of power. In an age when there was very little separation between religion and
government this also caused a shift in the power of the church. Constantine made Christianity
the state religion of the empire and also wished to reallocate the power from Rome to
Constantinople. The start of the split between the Roman Catholic church and the Eastern
Orthodox church occurred primarily because of disagreements in the church councils, which began
under the rule of Constantine. While the East and West were not officially split until 1054
(Great Schism) they were split on doctrine long before this. Christianity of the Eastern
Orthodox doctrine began to spread east and north into Russia.