The First Council of Nicaea was a council of Christian bishops convened in the Bithynian city of Nicaea by the Roman Emperor Constantine I in AD 325.
Theodoret of Cyrus or Cyrrhus was an influential theologian of the School of Antioch, biblical commentator, and Christian bishop of Cyrrhus (423–457). He played a pivotal role in several 5th-century Byzantine Church controversies that led to various ecumenical acts and schisms. He wrote against Cyril of Alexandria's 12 Anathemas which were sent to Nestorius and did not personally condemn Nestorius until the Council of Chalcedon. His writings against Cyril were included in the Three Chapters Controversy and were condemned at the Second Council of Constantinople. Some Chalcedonian and East Syriac Christians regard him as a "full" saint.
Alexander of Constantinople was a bishop of Byzantium and the first Archbishop of Constantinople. Scholars consider most of the available information on Alexander to be legendary.
Paul I or Paulus I or Saint Paul the Confessor, was the sixth bishop of Constantinople, elected first in 337 AD. Paul became involved in the Arian controversy which drew in the Emperor of the West, Constans, and his counterpart in the East, his brother Constantius II. Paul was installed and deposed three times from the See of Constantinople between 337 and 351. He was murdered by strangulation during his third and final exile in Cappadocia. His feast day is on November 6.
Macedonius was a Greek bishop of Constantinople from 342 up to 346, and from 351 until 360. He inspired the establishment of the Pneumatomachi, a sect later declared heretical.
Eudoxius was the eighth bishop of Constantinople from January 27, 360 to 370, previously bishop of Germanicia and of Antioch. Eudoxius was one of the most influential Arians.
Euphemius of Constantinople was Ecumenical Patriarch of Constantinople (490–496). Theophanes calls him Euthymius. Prior to his appointment, Euphemius was a presbyter of Constantinople, administrator of a hospital for the poor at Neapolis, unsuspected of any Eutychian leanings, and is described as learned and very virtuous.
Macedonius II, patriarch of Constantinople (495–511). For an account of his election see Patriarch Euphemius of Constantinople
John II, surnamed Cappadox or the Cappadocian was Patriarch of Constantinople in 518–520, during the reign of Byzantine emperor Anastasius I after an enforced condemnation of the Council of Chalcedon. His short patriarchate is memorable for the celebrated Acclamations of Constantinople, and the reunion of East and West after a schism of 34 years. At the death of Timothy I, John of Cappadocia, whom he had designated his successor, was presbyter and chancellor of the Church of Constantinople.
Acacius of Caesarea was a Christian bishop probably originating from Syria; Acacius was the pupil and biographer of Eusebius and his successor on the see of Caesarea Palestina. Acacius is remembered chiefly for his bitter opposition to Cyril of Jerusalem and for the part he was afterwards enabled to play in the more acute stages of the Arian controversy. The Acacian theological movement is named after him. In the twenty-first oration of St. Gregory Nazianzen, the author speaks of Acacius as being "the tongue of the Arians".
The Council of Ariminum, also known after the city's modern name as the Council of Rimini, was an early Christian church synod.
The Council of Seleucia was an early Christian church synod at Seleucia Isauria.
Paphnutius of Thebes, also known as Paphnutius the Confessor, was a disciple of Anthony the Great and a bishop of a city in the Upper Thebaid in the early fourth century. He is accounted by some as a prominent member of the First Council of Nicaea which took place in 325. Neither the name of his see nor the precise date of his death are known.
The First Synod of Tyre or the Council of Tyre was a gathering of bishops called together by Emperor Constantine I for the primary purpose of evaluating charges brought against Athanasius, the Patriarch of Alexandria.
The Arian controversy was a series of Christian disputes about the nature of Christ that began with a dispute between Arius and Athanasius of Alexandria, two Christian theologians from Alexandria, Egypt. The most important of these controversies concerned the relationship between the substance of God the Father and the substance of His Son.
The Pneumatomachi, also known as Macedonians or Semi-Arians in Constantinople and the Tropici in Alexandria, were an anti-Nicene Creed sect which flourished in the countries adjacent to the Hellespont during the latter half of the fourth, and the beginning of the fifth centuries. They denied the godhood of the Holy Ghost, hence the Greek name Pneumatomachi or 'Combators against the Spirit'.
Early Christianity spread from the Levant, across the Roman Empire, and beyond. Originally, this progression was closely connected to already established Jewish centers in the Holy Land and the Jewish diaspora. The first followers of Christianity were Jews or proselytes, commonly referred to as Jewish Christians and God-fearers.
Isaac was bishop of Seleucia-Ctesiphon, grand metropolitan and primate of the Church of the East from 399 to 410. He is included in the traditional list of patriarchs of the Church of the East.
Ursacius was the bishop of Singidunum, during the middle of the 4th century. Ursacius played an important role during the evolving controversies surrounding the legacies of the Council of Nicaea and the theologian Arius, acting frequently in concert with his fellow bishops of the Diocese of Pannonia, Germinius of Sirmium and Valens of Mursa. Found at various times during their episcopal careers staking positions on both sides of the developing theological debate and internal Church politicking, Ursacius and his fellows were seen to vacillate according to the political winds.
Valens of Mursa was bishop of Mursa and a supporter of Homoian theology, which is often labelled as a form of Arianism, although semi-Arianism is probably more accurate.