Arianism is a Christological doctrine considered heretical by all modern mainstream branches of Christianity. It is first attributed to Arius, a Christian presbyter who preached and studied in Alexandria, Egypt. Arian theology holds that Jesus Christ is the Son of God, who was begotten by God the Father with the difference that the Son of God did not always exist but was begotten/made before time by God the Father; therefore, Jesus was not coeternal with God the Father, but nonetheless Jesus began to exist outside time.
The Council of Chalcedon was the fourth ecumenical council of the Christian Church. It was convoked by the Roman emperor Marcian. The council convened in the city of Chalcedon, Bithynia from 8 October to 1 November 451. The council was attended by over 520 bishops or their representatives, making it the largest and best-documented of the first seven ecumenical councils. The principal purpose of the council was to re-assert the teachings of the ecumenical Council of Ephesus against the teachings of Eutyches and Nestorius. Such doctrines viewed Christ's divine and human natures as separate (Nestorianism) or viewed Christ as solely divine (monophysitism).
An ecumenical council, also called general council, is a meeting of bishops and other church authorities to consider and rule on questions of Christian doctrine, administration, discipline, and other matters in which those entitled to vote are convoked from the whole world (oikoumene) and which secures the approbation of the whole Church.
The First Council of Nicaea was a council of Christian bishops convened in the Bithynian city of Nicaea by the Roman Emperor Constantine I. The Council of Nicaea met from May until the end of July 325.
The First Council of Constantinople was a council of Christian bishops convened in Constantinople in AD 381 by the Roman Emperor Theodosius I. This second ecumenical council, an effort to attain consensus in the church through an assembly representing all of Christendom, except for the Western Church, confirmed the Nicene Creed, expanding the doctrine thereof to produce the Niceno-Constantinopolitan Creed, and dealt with sundry other matters. It met from May to July 381 in the Church of Hagia Irene and was affirmed as ecumenical in 451 at the Council of Chalcedon.
The Nicene Creed, also called the Creed of Constantinople, is the defining statement of belief of Nicene Christianity and in those Christian denominations that adhere to it.
The Council of Ephesus was a council of Christian bishops convened in Ephesus in AD 431 by the Roman Emperor Theodosius II. This third ecumenical council, an effort to attain consensus in the church through an assembly representing all of Christendom, confirmed the original Nicene Creed, and condemned the teachings of Nestorius, Patriarch of Constantinople, who held that the Virgin Mary may be called the Christotokos, "Christ-bearer" but not the Theotokos, "God-bearer". It met from 22 June to 31 July 431 at the Church of Mary in Ephesus in Anatolia.
The Second Council of Constantinople is the fifth of the first seven ecumenical councils recognized by both the Eastern Orthodox Church and the Catholic Church. It is also recognized by the Old Catholics and others. Protestant opinions and recognition of it are varied. Some Protestants, such as Calvinists, recognize the first four councils, whereas Lutherans and most Anglo-Catholics accept all seven. Constantinople II was convoked by the Byzantine Emperor Justinian I under the presidency of Patriarch Eutychius of Constantinople. It was held from 5 May to 2 June 553. Participants were overwhelmingly Eastern bishops—only sixteen Western bishops were present, including nine from Illyricum and seven from Africa, but none from Italy—out of the 152 total.
The East–West Schism, also known as the Great Schism or the Schism of 1054, is the break of communion between the Catholic Church and the Eastern Orthodox Church since 1054. A series of ecclesiastical differences and theological disputes between the Greek East and Latin West preceded the formal split that occurred in 1054. Prominent among these were the procession of the Holy Spirit (Filioque), whether leavened or unleavened bread should be used in the Eucharist, iconoclasm, the coronation of Charlemagne as Emperor of the Romans in 800, the Pope's claim to universal jurisdiction, and the place of the See of Constantinople in relation to the pentarchy.
The Quinisext Council, 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.
Pentarchy was a model of Church organization formulated in the laws of Emperor Justinian I of the Roman Empire. In this model, the Christian Church is governed by the heads (patriarchs) of the five major episcopal sees of the Roman Empire: Rome, Constantinople, Alexandria, Antioch, and Jerusalem.
Eutychianism, also known as Real Monophysitism, refers to a set of Christian theological doctrines derived from the ideas of Eutyches of Constantinople. Eutychianism is a monophysite understanding of how the human and divine relate within the person of Jesus Christ, with Christ being in one nature and of two, with the humanity of Christ subsumed by the divinity.
According to the Catholic Church, a Church Council is ecumenical ("world-wide") if it is "a solemn congregation of the Catholic bishops of the world at the invitation of the Pope to decide on matters of the Church with him". The wider term "ecumenical council" relates to Church councils recognised by both Eastern and Western Christianity.
Christianity in the 4th century was dominated in its early stage by Constantine the Great and the First Council of Nicaea of 325, which was the beginning of the period of the First seven Ecumenical Councils (325–787), and in its late stage by the Edict of Thessalonica of 380, which made Nicene Christianity the state church of the Roman Empire.
In the 5th century in Christianity, there were many developments which led to further fracturing of the State church of the Roman Empire. Emperor Theodosius II called two synods in Ephesus, one in 431 and one in 449, that addressed the teachings of Patriarch of Constantinople Nestorius and similar teachings. Nestorius had taught that Christ's divine and human nature were distinct persons, and hence Mary was the mother of Christ but not the mother of God. The Council rejected Nestorius' view causing many churches, centered on the School of Edessa, to a Nestorian break with the imperial church. Persecuted within the Roman Empire, many Nestorians fled to Persia and joined the Sassanid Church thereby making it a center of Nestorianism. By the end of the 5th century, the global Christian population was estimated at 10-11 million. In 451 the Council of Chalcedon was held to clarify the issue further. The council ultimately stated that Christ's divine and human nature were separate but both part of a single entity, a viewpoint rejected by many churches who called themselves miaphysites. The resulting schism created a communion of churches, including the Armenian, Syrian, and Egyptian churches, that is today known as Oriental Orthodoxy. In spite of these schisms, however, the imperial church still came to represent the majority of Christians within the Roman Empire.
During the 6th century, Roman Emperor Justinian I launched a military campaign in Constantinople to reclaim the western provinces from the Germans, starting with North Africa and proceeding to Italy. Though he was temporarily successful in recapturing much of the western Mediterranean he destroyed the urban centers and permanently ruined the economies in much of the West. Rome and other cities were abandoned. In the coming centuries the Western Church, as virtually the only surviving Roman institution in the West, became the only remaining link to Greek culture and civilization.
Christianity in late antiquity traces Christianity during the Christian Roman Empire — the period from the rise of Christianity under Emperor Constantine, until the fall of the Western Roman Empire. The end-date of this period varies because the transition to the sub-Roman period occurred gradually and at different times in different areas. One may generally date late ancient Christianity as lasting to the late 6th century and the re-conquests under Justinian of the Byzantine Empire, though a more traditional end-date is 476, the year in which Odoacer deposed Romulus Augustus, traditionally considered the last western emperor.
In the year before the Council of Constantinople in 381, Christianity became the official religion of the Roman Empire when Emperor Theodosius I issued the Edict of Thessalonica in 380, which recognized the catholic orthodoxy of Nicene Christians as the Roman Empire's state religion. Historians refer to the Nicene church associated with emperors in a variety of ways: as the catholic church, the orthodox church, the imperial church, the Roman church, or the Byzantine church, although some of those terms are also used for wider communions extending outside the Roman Empire. The Eastern Orthodox Church, Oriental Orthodoxy, and the Catholic Church all claim to stand in continuity from the Nicene church to which Theodosius granted recognition.
The history of Eastern Orthodox Christian theology begins with the life of Jesus and the forming of the Christian Church. Major events include the Chalcedonian schism of 451 with the Oriental Orthodox miaphysites, the Iconoclast controversy of the 8th and 9th centuries, the Photian schism (863-867), the Great Schism between East and West, and the Hesychast controversy. The period after the end of the Second World War in 1945 saw a re-engagement with the Greek, and more recently Syriac Fathers that included a rediscovery of the theological works of St. Gregory Palamas, which has resulted in a renewal of Orthodox theology in the 20th and 21st centuries.
The Papacy in late antiquity was a period in papal history between 313, when the Peace in the Church began, and the pontificate of Simplicius in 476, when the Roman Empire of the West fell.
