When Theodosius ascended to the imperial throne in 380, he began on a campaign to bring the Eastern Church back to Nicene Christianity.

Theodosius wanted to further unify the entire empire behind the orthodox position and decided to convene a church council to resolve matters of faith and discipline.

After the death of Constantine I in 337 and the accession of his Arian-leaning son Constantius II, open discussion of replacing the Nicene creed itself began.

[citation needed] Nicene Christianity also had its defenders: apart from Athanasius, the Cappadocian Fathers' Trinitarian discourse was influential in the council at Constantinople.

[citation needed] Theodosius' strong commitment to Nicene Christianity involved a calculated risk because Constantinople, the imperial capital of the Eastern Empire, was solidly Arian.

To complicate matters, the two leading factions of Nicene Christianity in the East, the Alexandrians and the supporters of Meletius in Antioch, were "bitterly divided ... almost to the point of complete animosity".

A group led by Maximus the Cynic gained the support of Patriarch Peter of Alexandria by playing on his jealousy of the newly created see of Constantinople.

They conceived a plan to install a cleric subservient to Peter as bishop of Constantinople so that Alexandria would retain the leadership of the Eastern Churches.

[citation needed] In any event, the plot was set into motion when, on a night when Gregory was confined by illness, the conspirators burst into the cathedral and commenced the consecration of Maximus as bishop of Constantinople.

The magistrates appeared with their officers; Maximus and his consecrators were driven from the cathedral, and ultimately completed the tonsure in the tenement of a flute-player.

[12] The news of the brazen attempt to usurp the episcopal throne aroused the anger of the local populace among whom Gregory was popular.

Theodosius committed the matter to Ascholius, the much respected bishop of Thessalonica, charging him to seek the counsel of Pope Damasus I.

[16] The first order of business before the council was to declare the clandestine consecration of Maximus invalid, and to confirm Theodosius' installation of Gregory Nazianzus as Archbishop of Constantinople.

[17]: 359  Ayres goes further and asserts that Gregory quickly made himself unpopular among the bishops by supporting the losing candidate for the bishopric of Antioch and vehemently opposing any compromise with the Homoiousians.

[22][21][20]The third canon was a first step in the rising importance of the new imperial capital, just fifty years old, and was notable in that it demoted the patriarchs of Antioch and Alexandria.

It originally did not elicit controversy, as the Papal legate Paschasinus and a partisan of his, Diogenes of Cyzicus, reference the canon as being in force during the first session of the Council of Chalcedon.

Pope Leo the Great,[27] declared that this canon had never been submitted to Rome and that their lessened honor was a violation of the Nicene council order.

After the Great Schism of 1054, in 1215 the Fourth Lateran Council declared, in its fifth canon, that the Roman Church "by the will of God holds over all others pre-eminence of ordinary power as the mother and mistress of all the faithful".

The Eastern Orthodox Church in some places (e.g. Russia) has a feast day for the Fathers of the First Six Ecumenical Councils on the Sunday nearest to July 13[39] and on May 22.