The fourth canon of the First Council of Nicaea of 325 attributed to the bishop of the capital (metropolis) of each Roman province (the "metropolitan bishop") a position of authority among the bishops of the province, without reference to the founding figure of that bishop's see. Its sixth canon recognized the wider authority, extending beyond a single province, traditionally held by Rome and Alexandria, and the prerogatives of the churches in Antioch and the other provinces. Of Aelia, the Roman city built on the site of the destroyed city of Jerusalem, the council's seventh canon reads: "Since custom and ancient tradition have prevailed that the Bishop of Aelia should be honoured, let him, saving its due dignity to the Metropolis, have the next place of honour." The metropolis in question is generally taken to be Caesarea Maritima, though in the late 19th century Philip Schaff also mentioned other views.
This Council of Nicaea, being held in 325, of course made no mention of Constantinople, a city which was only officially founded five years later, at which point it became the capital of the Empire. But the First Council of Constantinople (381) decreed in a canon of disputed validity: "The Bishop of Constantinople, however, shall have the prerogative of honour after the Bishop of Rome; because Constantinople is New Rome." A century after the Council of Chalcedon (451) and the ensuing schism between those who accepted it and those who rejected it, Eastern Orthodox Christianity wove these two sources together to develop the theory of the Pentarchy: "[F]ormulated in the legislation of the emperor Justinian I (527–565), especially in his Novella 131, the theory received formal ecclesiastical sanction at the Council in Trullo (692), which ranked the five sees as Rome, Constantinople, Alexandria, Antioch, and Jerusalem." Earlier, the Council of Ephesus decreed in 431 that the Church of Cyprus should be autocephalous, against the claims of Antioch, the capital of the Roman diocese of the East, of which Cyprus was part.
Listing of the sees
The patriarchs of these four sees consider themselves to be successors of those given special status in these canons:
In Catholic canon law, the term is applied also to the various departments of the Roman Curia. The Code of Canon Law states: "In this Code the terms Apostolic See or Holy See mean not only the Roman Pontiff, but also, unless the contrary is clear from the nature of things or from the context, the Secretariat of State, the Council for the public affairs of the Church, and the other Institutes of the Roman Curia." The bodies in question are seen as speaking on behalf of the See of Rome.
^Schaff's Seven Ecumenical Councils: First Nicaea: Canon VII: "It is very hard to determine just what was the 'precedence' granted to the Bishop of Ælia, nor is it clear which is the metropolis referred to in the last clause. Most writers, including Hefele, Balsamon, Aristenus and Beveridge consider it to be Cæsarea; while Zonaras thinks Jerusalem to be intended, a view recently adopted and defended by Fuchs; others again suppose it is Antioch that is referred to."
^Commemorative coins that were issued during the 330s already refer to the city as Constantinopolis (see e.g. Michael Grant, The climax of Rome (London 1968), p. 133), or "Constantine's City". According to the Reallexikon für Antike und Christentum, vol. 164 (Stuttgart 2005), column 442, there is no evidence for the tradition that Constantine officially dubbed the city "New Rome" (Nova Roma). It is possible that the emperor called the city "Second Rome" (Greek: Δευτέρα Ῥώμη, Deutéra Rhōmē) by official decree, as reported by the 5th-century church historian Socrates of Constantinople: see Names of Constantinople.
^Professor Sergew Hable Sellassie & Professor Tadesse Tamerat (December 1970), "The Establishment of the Ethiopian Church", The Church of Ethiopia: A Panorama Of History and Spiritual Life, archived from the original on 11 June 2011, retrieved 2 December 2015 – via Ethiopianorthodox.org
^"In the east there were many Churches whose foundation went back to the Apostles; there was a strong sense of the equality of all bishops, of the collegial and conciliar nature of the Church. The east acknowledged the Pope as the first bishop in the Church, but saw him as the first among equals. In the west, on the other hand, there was only one great see claiming Apostolic foundation — Rome — so that Rome came to be regarded as the Apostolic see" (Bishop Kallistos Ware, Orthodox Church).
^"An Apostolic see is any see founded by an Apostle and having the authority of its founder; the Apostolic See is the seat of authority in the Roman Church, continuing the Apostolic functions of Peter, the chief of the Apostles. Heresy and barbarian violence swept away all the particular Churches which could lay claim to an Apostolic see, until Rome alone remained; to Rome, therefore, the term applies as a proper name" (Catholic Encyclopedia, article The Apostolic See).