Exactly nine hundred years have passed since the separation of the two great Churches of Christendom when the Western Church broke away from the Eastern Orthodox. Many still seek the cause of this most unfortunate division. Actually, it can be found in the difference concerning the Primacy of the Pope of Rome.
Until the Fifth Century A.D. there was not even a single instance of dissention or antagonism between the two Churches. The bishop of Rome had always been considered the First in the order of hierarchy. This was a natural consequence of the position of Rome as the capital of the Roman Empire. When Constantinople became the new capital of the Byzantine State its Bishop assumed the second position in the ranks of hierarchy. The third canon of the Second Ecumenical Council (381) designates the position of honor of the Bishop of Constantinople as second only to that of the Bishop of Rome. This decision of the Council is based on the premise that Constantinople is the new Rome, and incidentally, it has been retained among the titles of the Patriarch of Constantinople.