I've always wondered how Constantinople could claim to be a "patriarchate" as it was not one of the original apostolic sees (the others being Rome, Jerusalem, Antioch, and Alexandria).
I claim relative ignorance here. Can someone shed light on this?
Constantinople's claim to be a patriarchate was a journey in itself. In culminated in the passage of canon 28 at the Council of Chalcedon (which almost entirely consisted of eastern bishops), which placed Constantinople over all the other patriarchates except Rome. Canon 28 is the linchpin to their claims of being all that and a bag of chips, and came about because of the growing ambition of Constantinople. It was the center of the empire, and they figured they had a right to consolidate and appropriate power. What they will never tell you, however, is that the papal representatives at the council objected to Canon 28, it was passed in the middle of the night when the papal representatives weren't present, and Pope Leo the Great nullified that canon "by the authority of blessed Peter".
Read the acts of the council of Chalcedon itself, as well as the letters of Leo the Great to Emperor Marcian, Empress Pulcharia, Patriarch Anatolius, and John of Cos. It paints a vivid picture of what really happened.
Letter 132, which is a letter of Anatolius (Patriarch of Constantinople) to Leo, is pure gold. In it, Anatolius acknowledges Pope Leo's right to approve or disapprove any part of the council, he protests that his great desire is to "obey" Leo in all things, and he accedes to Leo's commands to correct two unjust administrative changes involving two individuals at the local level in Constantinople (the restoration of a Catholic who unjustly lost his job, and the dismissal of a heretic who had been protected by Anatolius).
The end result is that Canon 28 pretty much disappeared for the next several centuries, being resurrected by Photius and, to a greater extent, by Michael Cerularius in the 11th century. Michael was worse than Photius, in that it was his actions that were responsible for the more permanent separation of Rome and Constantinople.
It's important to note that, while Constantinople dropped Canon 28 after Leo nullified it, they continued to behave as if it was in force.
The Greeks returned to the Faith and submission to Rome twice after Cerularius. Once at the second council of Lyons (1274), and the other at the Council of Florence (1439). Florence was the biggest, and it had amazing results. The last two emperors of the Byzantine empire (John VIII Palaiologos and Constantine XI Palaiologos) died as Catholics in submission to the Pope, and the entire reason they went into schism again after the Council of Florence is because of the Turks. Mehmet the II took Constantinople on Pentecost in 1453, and installed a new patriarch (while the Catholic Patriarch was in Rome) named Gennadius Scholarius, who was the most anti-Catholic bishop he could find. Scholarius was a protege of Mark of Ephesus, who was the only bishop in the east who refused to sign the docuмents of the Council of Florence. Mark went back to Constantinople after the council and caused all sorts of trouble, stirring the people up against the reunion.
Gennadius Scholarius, on being chosen as the new Patriarch, processed through the streets of Constantinople and received the symbols of his new office directly from the hands of Mehmet II, an Ottoman Turk. This scene is immortalized in a number of Greek icons.
Why anyone would look at the claims of Orthodoxy seriously is beyond me.