The Eastern Orthodox Church
As the Christian faith evolved, its spread was facilitated greatly by both the Roman and Byzantine Empires. Emperors of these powerful nations not only practiced Christianity, but eventually made it the official religion of their states.
The result was that the affairs of the church became closely tied to the political affairs of the empire. Leaders of these empires exerted great control and influence over the developing religion.
In Rome, the Bishop, known as the Pope, gradually grew in authority, until he was recognized throughout the western world as the highest authority in the Church.
The Patriarch of Constantinople did not, however, recognize this authority. The Byzantines felt that their Patriarch was an equal to the Pope, and looked to their own patriarch for leadership. The Byzantine emperor also held a great deal of authority in matters of the church, and often settled doctrinal conflicts.