Eusebius of Nicomedia was an Arian priest who baptized Constantine the Great on his deathbed in 337. A fifth-century legend evolved that Pope Saint Sylvester I was the one to baptize Constantine, but this is dismissed by scholars as a forgery 'to amend the historical memory of the Arian baptism that the emperor received at the end of his life, and instead to attribute an unequivocally orthodox baptism to him.' He was a bishop of Berytus in Phoenicia. He was later made the bishop of Nicomedia, where the Imperial court resided. He lived finally in Constantinople from 338 up to his death.
Pope Julius I was the bishop of Rome from 6 February 337 to his death on 12 April 352. He is notable for asserting the authority of the pope over the Arian Eastern bishops, as well as a dubious claim that he set 25 December as the official birthdate of Jesus.
Pope Felix III was the bishop of Rome from 13 March 483 to his death. His repudiation of the Henotikon is considered the beginning of the Acacian schism. He is commemorated on March 1.
Saint Meletius was a Christian bishop of Antioch from 360 until his death in 381. He was opposed by a rival bishop named Paulinus and his episcopate was dominated by the schism, usually called the Meletian schism. As a result, he was exiled from Antioch in 361–362, 365–366 and 371–378. One of his last acts was to preside over the First Council of Constantinople in 381.
St. Flavian II of Antioch was the Patriarch of Antioch from 498 until his deposition in 512.
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.
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.
Eustathius of Antioch, sometimes surnamed the Great, was a Christian bishop and archbishop of Antioch in the 4th century. His feast day in the Orthodox Church is February 21.
Saint Leander of Seville was the Bishop of Seville. He was instrumental in effecting the conversion of the Visigothic kings Hermengild and Reccared to Catholicism. His brother was the encyclopedist St. Isidore of Seville.
Eusebius of Vercelli was a bishop from Sardinia and is counted a saint. Along with Athanasius, he affirmed the divinity of Jesus against Arianism.
Lucian of Antioch, known as Lucian the Martyr, was a Christian presbyter, theologian and martyr. He was noted for both his scholarship and ascetic piety.
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".
Lucifer of Cagliari was a bishop of Cagliari in Sardinia known for his passionate opposition to Arianism. He is venerated as a Saint in Sardinia, though his status remains controversial.
Beginning with three synods convened between 264 and 269 in the matter of Paul of Samosata, more than thirty councils were held in Antioch in ancient times. Most of these dealt with phases of the Arian and of the Christological controversies. For example, the Catholic Encyclopedia article on Paul of Samosata states:
It must be regarded as certain that the council which condemned Paul rejected the term homoousios; but naturally only in a false sense used by Paul; not, it seems because he meant by it a unity of Hypostasis in the Trinity, but because he intended by it a common substance out of which both Father and Son proceeded, or which it divided between them, — so St. Basil and St. Athanasius; but the question is not clear. The objectors to the Nicene doctrine in the fourth century made copious use of this disapproval of the Nicene word by a famous council.
Anastasius I of Antioch was the Patriarch of Antioch twice.
Possidius was a friend of Augustine of Hippo who wrote a reliable biography and an indiculus or list of his works. He was bishop of Calama in the Roman province of Numidia.
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'.
Philogonius was a lawyer and an early Bishop of Antioch who came to be considered a saint. He opposed Arianism when that heresy emerged in Alexandria, Egypt. His feast day is 20 December.
Saint Julian Sabas was a hermit who spent most of his life in deserted parts of Syria, but left his cell for a short period to denounce Arianism. His feast day is 14 January or 18 October in the Roman Church.
Saint Potamon of Heraclea was a bishop of Heraclea in Egypt who was persecuted under the emperor Maximinus Daza, attended the First Council of Nicaea, then was martyred in Egypt by the Arians. His feast day is 18 May.
