eight councils of the Christian church, held at Constantinople. In the Western church, only four of these councils are recognized as ecumenical: the first three and the sixth, which is called the Fourth Council of Constantinople.

First Council of Constantinople

(381). This council was the second ecumenical council of the church. It was convened by Theodosius I, the emperor of the East. The 150 bishops meeting at the council condemned various religious sects as heretical, reaffirmed the resolutions of the first ecumenical council of Nicaea (325), defined the Holy Spirit as consubstantial and coeternal with the Father and the Son in the divine Trinity, and proclaimed the bishop of Constantinople second in precedence to the bishop of Rome.

Second Council of Constantinople

(553). This meeting at Constantinople was the fifth ecumenical council of the church. It was convoked by Justinian I, Byzantine emperor, to consider the writings of the Greek theologians Theodore of Mopsuestia, Theodoret of Cyrrhus (c. 386–c. 457), and Ebas of Edessa (380?–457?). These writings, known as the Three Chapters, had been approved by the fourth ecumenical council, held at Chalcedon in 451. The council of 553, however, condemned the Three Chapters and anathematized their authors.

Third Council of Constantinople

(680). The third council held at Constantinople was the sixth ecumenical council. It met at the request of Constantine IV (c. 652–85), Byzantine emperor (r. 668–85), to condemn Monothelitism, a doctrine declaring that Jesus Christ had only one will, even though he had two natures (human and divine).

Fourth Council of Constantinople

(691). The fourth meeting held at Constantinople was called by Justinian II (669–711), Byzantine emperor (r. 685–95; 705–11), to enact a legislative code for the church. This code later became part of the canon law of the Orthodox church, but was largely rejected by the church in the West. The council of 691 was regarded in the East as supplementary to the previous ecumenical councils (the fifth and sixth) and is therefore known as the Quinisext Synod (Lat., “fifth-sixth”). This council was also sometimes called the Trullan Synod from its meeting place in the trullum (“dome”) of the emperor’s palace.

Fifth Council of Constantinople

(754). The fifth council at Constantinople was called by Constantine V (718–75), Byzantine emperor (r. 741–75), to deal with the problem of image worship. The council condemned the worship of images; this position, however, was rejected by the seventh ecumenical council, held at Nicaea in 787, and the council of 754 was not recognized as ecumenical in the West.

Sixth Council of Constantinople

(869–70). The sixth meeting at Constantinople is considered the Fourth Council of Constantinople by the Western church and is recognized as the eighth ecumenical council. It was convened by Basil I, Byzantine emperor, to confirm his deposition of Photius, patriarch of Constantinople. Photius, who was the principal instigator of the 9th-century schism between the Eastern and Western churches, was formally deposed. The council of 869–70 was not recognized by the Eastern church.

Seventh Council of Constantinople

(879). The seventh assembly at Constantinople was recognized in the East as the eighth ecumenical council of the church. It was called by Photius, who had been reinstated as the patriarch of Constantinople in the previous year. This council, which repudiated the council of 869–70, was not recognized by the church in the West.

Eighth Council of Constantinople

(1341). The last council held at Constantinople was recognized in the East as the ninth ecumenical council of the church. It was held to deal with the problem of the Hesychasts, a mystical sect of monks living on Mount Áthos. The council condemned the Greek monk Barlaam (c. 1290–c. 1350) as a heretic for his opposition to the sect. See also HERESY,.