Arianism is a Christological doctrine considered heretical by all 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 as time applies only to the creations of God.
Athanasius I of Alexandria, also called Athanasius the Great, Athanasius the Confessor, or, among Coptic Christians, Athanasius the Apostolic, was a Christian theologian and the 20th pope of Alexandria. His intermittent episcopacy spanned 45 years, of which over 17 encompassed five exiles, when he was replaced on the order of four different Roman emperors. Athanasius was a Church Father, the chief defender of Trinitarianism against Arianism, and a noted Egyptian Christian leader of the fourth century.
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.
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.
Arius was a Cyrenaic presbyter, ascetic, and priest. Traditionally, it was claimed that Arius was the founder of the doctrine of Arianism but, more recently, Rowan Williams stated that "Arius' role in 'Arianism' was not that of the founder of a sect. It was not his individual teaching that dominated the mid-century eastern Church."
The Third Council of Toledo (589) marks the entry of Visigothic Spain into the Catholic Church, and is known for codifying the filioque clause into Western Christianity. The council also enacted restrictions on Jews, and the conversion of the country to Catholic Christianity led to repeated conflict with the Jews.
The Acacians, or perhaps better described as the Homoians or Homoeans, were a non-Nicene branch of Christianity that dominated the church during much of the fourth-century Arian Controversy. They declared that the Son was similar to God the Father, without reference to substance (essence). Homoians played a major role in the Christianization of the Goths in the Danubian provinces of the Roman Empire.
The Councils of Sirmium were the five episcopal councils held in Sirmium in 347, 351, 357, 358 and finally in 375 or 378. The third—the most important of the councils—marked a temporary compromise between Arianism and the Western bishops of the Christian church. At least two of the other councils also dealt primarily with the Arian controversy. All of these councils were held under the rule of Constantius II, who was sympathetic to the Arians.
Melitius or Meletius was bishop of Lycopolis in Egypt. He is known mainly as the founder and namesake of the Melitians, one of several schismatic sects in early church history which were concerned about the ease with which lapsed Christians reentered the Church.
Semi-Arianism was a position regarding the relationship between God the Father and the Son of God, adopted by some 4th-century Christians. Though the doctrine modified the teachings of Arianism, it still rejected the doctrine that Father, Son, and Holy Spirit are co-eternal, and of the same substance, or consubstantial, and was therefore considered to be heretical by many contemporary Christians.
Marcellus of Ancyra was a Bishop of Ancyra and one of the bishops present at the Council of Ancyra and the First Council of Nicaea. He was a strong opponent of Arianism, but was accused of adopting the opposite extreme of modified Sabellianism. He was condemned by a council of his enemies and expelled from his see, though he was able to return there to live quietly with a small congregation in the last years of his life. He is also said to have destroyed the temple of Zeus Belos at Apamea.
Ptolemais was one of the five cities that formed the Pentapolis of Cyrenaica, the others being Cyrene, Euesperides, Tauchira/Teuchira, and Apollonia.
Alexander I of Alexandria was the 19th Pope and Patriarch of Alexandria. During his patriarchate, he dealt with a number of issues facing the Church in that day. These included the dating of Easter, the actions of Meletius of Lycopolis, and the issue of greatest substance, Arianism. He was the leader of the opposition to Arianism at the First Council of Nicaea. He also mentored his successor, Athanasius of Alexandria, who would become one of the Church Fathers.
Homoiousios is a Christian theological term, coined in the 4th century to identify a distinct group of Christian theologians who held the belief that God the Son was of a similar, but not identical, essence with God the Father.
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.
In the history of Christianity, the first seven ecumenical councils include the following: 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 680–681 and finally, the Second Council of Nicaea in 787. All of the seven councils were convened in what is now the country of Turkey.
Constantine the Great's (272–337) relationship with the four Bishops of Rome during his reign is an important component of the history of the Papacy, and more generally the history of the Catholic Church.
Arian creeds are the creeds of Arian Christians, developed mostly in the fourth century when Arianism was one of the main varieties of Christianity.
Zopyrus, (Ζώπυρος) was a bishop of the ancient Roman Town of Barca in Cyrenica,.
Theodotus was the bishop of Laodicea in Syria from the early 300s. He replaced Stephen, who apostasized during the Great Persecution (303–313). The exact year of his consecration cannot be fixed more precisely. He attended at least four church councils.
