The Ecumenical Patriarchate of Constantinople is the surviving legacy of a religious empire that dominated the affairs of Christians worldwide for more than 1,100 years. After the fall of Rome in A.D. 476, Constantinople inherited unrivaled leadership of the Christian world under the names "Rome of the East" and "New Rome." The Greeks, Bulgarians, Serbians, Romanians, Albanians, and Georgians who adhered to the Eastern Orthodox creed were referred to as "Romans" (thus the reason why many an Istanbul church includes the word "Rum" in its title). While the pope continued to reject the primacy of the Bishop of Constantinople (soon after given the title of Archbishop), the influence of the Patriarch of Constantinople nevertheless grew under the patronage of the emperor. The initial seat of the Patriarchate was pre-Constantine Hagia Eirene, now in the first court of Topkapi Palace. Upon Justinian's completion of the Ayasofya, the Church was rooted here for the next 916 years (with a brief respite when the Byzantine Court was forced to flee to Nicaea after the Fourth Crusade in 1204). The Ottoman conquest displaced the Patriarchate to the Havariyun (or Church of the Twelve Apostles, now lost under Fatih Camii), before it moved to the Church of the Pammakaristos (Fethiye Camii) in 1456. In 1587, the Eastern Orthodox Church moved to the Church of the Virgin Mary in Vlah Palace, and then to St. Demetrios in Balat. The Patriarchate settled into its current spot in the Church of St. George (Ayios Yeoryios) in 1601. In the 19th century, assertions of national independence and religious autonomy whittled the influence of the Patriarchate, until its reach was constricted to the borders of the Turkish Republic and a mere handful of semiautonomous communities abroad. Still, the Orthodox community considers the Ecumenical Patriarchate one of the two most prominent Christian institutions in the world, the other being the Holy See in Rome. Today, the Patriarch and Archbishop of Constantinople is primus inter pares or "first among equals," among the 14 autonomous and semiautonomous Patriarchates-in-communion that make up the Eastern Orthodox Church.
The present church was built in 1720 on a traditional basilica plan. It seems to lack the grandeur one would expect of its station, but the building was constructed under the Ottoman prohibition against non-Muslim use of domes or masonry roofs on their places of worship. Instead, it is topped by a timber roof. The gilded iconostasis provides some insight into the opulence one imagines of Byzantium. The Patriarchal Throne is believed to date to St. John Chrysostom Patriarchate in the 5th century A.D. His relics and those of St. Gregory the Theologian, which were hijacked after the 1204 Crusader sacking of the city, were brought back from Rome by Patriarch Bartholomew in 2004. In the aisle opposite these relics are the remains of the female saints, St. Euphemia, St. Theophano, and St. Solomone. There are also three invaluable gold mosaic icons including one of the Virgin, as well as the Column of Flagellation. The small complex is comprised of the modest Cathedral, the Patriarchate Library, administrative offices, and the Ayios Harambalos spring.