Almost from the very beginning, Christians referred to the Church as the “One, Holy, Catholic (from the Greek καθολική, or “according to the whole, universal”) and Apostolic Church”. The Orthodox Church claims that it is today the continuation and preservation of that same Church.
A number of other Christian churches also make a similar claim: the Roman Catholic Church, the Anglican Communion, the Assyrian Church and the Oriental Orthodox Churches. In the Orthodox view, the Assyrians and Orientals left the Orthodox Church in the years following the Third Ecumenical Council of Ephesus (431) and the Fourth Ecumenical Council of Chalcedon (451), respectively, in their refusal to accept those councils’ Christological definitions. Similarly, the churches in Rome and Constantinople separated in an event known as the East–West Schism, traditionally dated to the year 1054, although it was more a gradual process than a sudden break. The Church of England separated from the Roman Catholic Church, not directly from the Orthodox Church, for the first time in the 1530s (and, after a brief reunion in 1555, again finally in 1558). Thus, though it was united to Orthodoxy when established through the work of Saint Augustine of Canterbury in the early 7th century, its separation from Orthodoxy came about indirectly through the See of Rome.
To all these churches, the claim to catholicity (universality, oneness with the ancient church) is important for multiple doctrinal reasons that have more bearing internally in each church than in their relation to the others, now separated in faith. The meaning of holding to a faith that is true is the primary reason why anyone’s statement of which church split off from which other has any significance at all; the issues go as deep as the schisms. The depth of this meaning in the Orthodox Church is registered first in its use of the word “Orthodox” itself, a union of Greek orthos (“straight” “correct” “true” “right”) and doxa (“glory” as in Doxa Patri, “Glory to the Father”).[
There have been a number of times when alternative theological ideas arose to challenge the Orthodox faith. At such times the Church deemed it necessary to convene a general or “Great” council of all available bishops throughout the world. The Church considers the first seven Ecumenical Councils (held between the 4th and the 8th centuries) to be the most important; however, there have been more, specifically the Synods of Constantinople, 879–880, 1341, 1347, 1351, 1583, 1819, and 1872, the Synod of Jassy (Iași), 1642, and the Pan-Orthodox Synod of Jerusalem, 1672, all of which helped to define the Orthodox position.
The ecumenical councils followed a democratic form, with each bishop having one vote. Though present and allowed to speak before the council, members of the Imperial Roman/Byzantine court, abbots, priests, monks and laymen were not allowed to vote. The primary goal of these Great Synods was to verify and confirm the fundamental beliefs of the Church as truth, and to remove as heresy any false teachings that would threaten the Church. The Pope of Rome, at that time, held the position of “first among equals”. And while he was not present at any of the councils he continued to hold this title until the East–West Schism of 1054 AD.
According to Orthodox teaching the position of “First Among Equals” gives no additional power or authority to the bishop that holds it, but rather that this person sits as organizational head of a council of equals (like a president). His words and opinions carry no more insight or wisdom than any other bishop. It is believed that the Holy Spirit guides the Church through the decisions of the entire council, not one individual. Additionally it is understood that even the council’s decisions must be accepted by the entire Church in order for them to be valid.
One of the decisions made by the First Council of Constantinople (the second ecumenical council, meeting in 381) and supported by later such councils was that the Patriarch of Constantinople should be given equal honor to the Pope of Rome since Constantinople was considered to be the “New Rome”. According to the third Canon of the second ecumenical council: “Because it is new Rome, the bishop of Constantinople is to enjoy the privileges of honor after the bishop of Rome.” This means that both enjoy the same privileges because they are both bishops of the imperial capitals, but the bishop of Rome will precede the bishop of Constantinople since Old Rome precedes New Rome.