The Eastern Orthodox Church draws its authority and its tradition primarily from the church of Constantinople. There are some Orthodox Christians who believe the Apostle Andrew founded the Church in Constantinople. This theory is not supported by documented history and is generally considered a medieval legend. There is no evidence that this church was established by the Apostles. Rather, it originated out of the 4th Century Eastern Roman Empire.
The Roman tradition, however, stems directly from the 1st Century and draws its authority from a church founded by the Apostles. And, unlike the Apostolic Eastern churches of Antioch and Alexandria (from which Constantinople essentially usurped authority and regional primacy for the sake of its political theocracy --the Eastern Empire / "Holy Byzantium"). Alexandria and Antioch (along with Constantinople and Jerusalem) formally embraced Arianism, Monphysism, Monothelitism, and Iconoclasm for extended periods of time. Thank God they were able to come out of these heresies and join in the ecumenical councils that condemned these heresies.
The church of Rome never formally embraced any heresy or had its Apostolic succession disturbed by heretical teaching. Some Orthodox Christians will point to the Filioque. There is a detailed article about this important issue here.
The orthodox integrity of the Eastern Church is dependent on the church of Rome, with which these Eastern churches sought to re-establish communion after these heresies. The Christian community of Rome is the same, unbroken Christian community that was established by St. Peter and St. Paul in the 1st Century. Byzantium cannot say this about itself, nor can the Antiochians, or the Alexandrians, or the Christians of Jerusalem. All these churches were either heretical for long periods or have ceased to exist for long periods (e.g. Jerusalem) or all-together (e.g. Antioch).
This does not mean that there is not a valid succession, or valid communion. However, this succession is dependent on Rome. The Orthodox Church most certainly has a valid Eucharist and that is why we seek reunion and communion with the East, in a way that they will remain distinctly eastern in their spirituality and liturgy. This type reunion would not possible for Protestant or Evangelicals communities, who have given up the Eucharist. However, reunion with the east would be very difficult while they currently embrace the modern heresies of contraception and divorce, both of which are condemned by the eastern Fathers of the Church.
Charis kai eirene (Grace and Peace)
Hugh wishes to thank Mark Bonocore for this article.
Lord Jesus, let Your prayer of unity for Christians
become a reality, in Your way.
We have absolute confidence
that you can bring your people together,
we give you absolute permission to move.