Third Council of Constantinople in the context of "Heresy"

In the history of Christianity, the first seven ecumenical councils are as follows: the First Council of Nicaea in 325, the First Council of Constantinople in 381, the Council of Ephesus in 431, the Council of Chalcedon in 451, the Second Council of Constantinople in 553, the Third Council of Constantinople from 680 to 681 and finally, the Second Council of Nicaea in 787.

These seven events represented an attempt by Church leaders to reach an orthodox consensus, restore peace and develop a unified Christendom. Among Eastern Christians the Eastern Orthodox, Oriental Orthodox, and Church of the East (Assyrian) churches and among Western Christians the Roman Catholic, Anglican, Utrecht and Polish National Old Catholic, and some Scandinavian Lutheran churches all trace the legitimacy of their clergy by apostolic succession back to this period and beyond, to the earlier period referred to as the Early Church.

The Quinisext Council (Latin: Concilium Quinisextum; Koine Greek: Πενθέκτη Σύνοδος, romanized: Penthékti Sýnodos, literally meaning, Fifth-Sixth Meeting), i.e., the Fifth-Sixth Council, often called the Council in Trullo, Trullan Council, or the Penthekte Synod, was a church council held in 692 at Constantinople under Justinian II.

The synod is known as the "Council in Trullo" because, like the Sixth Ecumenical Council, it was held in a domed hall in the Imperial Palace (τρούλος [troúlos], meaning a cup or dome). Both the Fifth and the Sixth Ecumenical Councils had omitted to draw up disciplinary canons, and as this council was intended to complete both in this respect, it took the name of Quinisext.

The Typos of Constans (also called Type of Constans) was an edict issued by Eastern Roman emperor Constans II in 648 in an attempt to defuse the confusion and arguments over the Christological doctrine of Monotheletism. For over two centuries, there had been a bitter debate regarding the nature of Christ: the orthodox Chalcedonian position defined Christ as having two natures in one person, whereas Miaphysite opponents contended that Jesus Christ possessed but a single nature. At the time, the Byzantine Empire had been at near constant war for fifty years and had lost large territories. It was under great pressure to establish domestic unity. This was hampered by the large number of Byzantines who rejected the Council of Chalcedon in favour of Monophysitism.

The Typos attempted to dismiss the entire controversy, on pain of dire punishment. This extended to kidnapping the Pope from Rome to try him for high treason and mutilating one of the Typos's main opponents. Constans died in 668. Ten years later his son, Constantine IV, fresh from a triumph over his Arab enemies and with the predominantly Monophysitic provinces irredeemably lost, called the Third Council of Constantinople. It decided with an overwhelming majority to condemn Monophysitism, Monotheletism, the Typos of Constans and its major supporters. Constantine put his seal to the Council's decisions, and reunited such of Christendom as was not under Arab suzerainty.

Monoenergism (Greek: μονοενεργητισμός) was a notion in early medieval Christian theology, representing the belief that Christ had only one "energy" (energeia). The teaching of one energy was propagated during the first half of the seventh century by Patriarch Sergius I of Constantinople. Opposition to dyoenergism, its counterpart, would persist until Dyoenergism was espoused as Orthodoxy at the Sixth Ecumenical Council and monoenergism was rejected as heresy.