Arius was a heretic of the early fourth century who taught that the Son of God was not eternal, that the Son was a created being, and was subordinate to God the Father. This belief was considered a heresy, called Arianism. that was condemned by the Ecumenical Council at Nicaea in 325. Yet, the controversy over the heresy continued after the Council as Arius returned to the favor of the Emperor. Only the unusual death of Arius, followed a year later by the death of Constantine, temporarily overshadowed the controversy.
Arius was apparently of Lybian and Berber descent, born about 250 in North Africa. His father is known as Ammonius. Arius grew up in Alexandria, Egypt at the time the city was the center of Christian scholarship. These also were the times when a theological explanation of the relationship between the Father and Son was being developed. Thus, Arius' teachings became one of the views that were proposed during these Christological controversies. Arius was a pupil of Lucian of Antioch, a celebrated Christian teacher and martyr. In 306, Arius sided with Meletius, another Egyptian schismatic, against the Bishop of Alexandria, Peter. But, their dispute was soon reconciled and Peter ordained Arius a deacon. Later, having fallen out again with Peter, Arius gained the friendship of Peter's successor, Achillas, who ordained Arius a priest in 313, thus giving Arius an official status. Apparently, Arius also had hopes of succeeding Achillas as patriarch of Alexandria. It was under Bishop Achillas that Arius first became controversial as reported by the historian Socrates Scholasticus. This occurred when Arius presented his syllogism :If the Father begat the Son, he that was begotten had a beginning of existence. From this it is evident that there was a time when the Son was not. It therefore necessarily follows that he had his substance from nothing.
In 318, Arius came into dispute with Bishop Alexander of Alexandria, who had succeeded Achillas, over his teachings of the fundamental truth God's divine Sonship and substance. While Arius developed a following among the Syrian prelates, an Alexandrian synod of some 100 bishops condemned him in 321. He was excommunicated and fled to Palestine. There he entered into a friendship with Eusebius of Nicomedia. Arius, a proficient writer, produced many compositions, in both prose and verse defending his belief, in a media he called Thalia. Most of these writings are not extant, having been destroyed as being heretical.
In opposition, Alexander of Alexandria presented his case to Alexander of Constantinople and Eusebius of Nicomedia, where the emperor was in residence. The arguments continued and became a powerful force within the Roman empire, such that the emperor Constantine could no longer ignore it. To settle the arguments he called a council with delegates drawn from all the empire. The purpose of this, the First Council of Nicaea, was to determine as far as possible what had been taught from the beginning. The Council met in Nicaea, near Constantinople in 325. Here the confession of faith presented by Arius was cut to pieces. Then, under the guidance of Constantine, the Council developed a creed, the Nicaean Creed for use in catechetical instruction and at baptisms, that rendered Arius' language heretical.
With this decision, Arius and his followers were deposed and sent into exile. Yet, much concern remained over the use of the word homoousios that was used in formulating the case against Arius. The early, ill defined definitions of homoousios were part of the arguments used in deposing Paul of Samosata in 269 which at the time were considered to have Sabellian tendencies. In his arguments against Arius, Alexander of Alexandria refined the definition to mollify the earlier objections. However, not all agreed.
So, the decision at Nicaea almost immediately came under attack and after Alexander died in 327 many of the supporters of Arius were allowed to returned to their old positions which allowed Eusebius of Nicomedia again to influence Constantine. Even Arius was allowed to return to Alexandria in 331, Many of the proponents of the Nicaean decision began to be deposed as they found it impossible to defend the decision without apparently falling into Sabellianism. Eustathius of Antioch, Marcellus of Ancyra, and others, who were supporters of Anthanasius of Alexandria, were among them.
With Constantine now favoring Arius, he commanded Anthanasius to readmit Arius to communion. This Anthanasius refused, thus leading to charges of treason to the emperor and exile to Trier. With their acceptance by the emperor, the supporters of Arius began disturbances in Alexandria toward gaining power. The emperor then directed Alexander of Constantinople to receive Arius into communion. Opposed to the reinstatement of Arius, Alexander asked his supporters to pray for removal of either him or Arius from this world before Arius was re-admitted to communion. And, the day before Arius was to receive communion, he died suddenly. That was 336.
The death of Arius and then that of Constantine a year later led to a lull in the controversy, but the ‘'Christological controversies would continue for several more centuries.