Arianism

The concern behind the position is easy to state sympathetically. God alone is unbegotten, without beginning and without cause, and that is what it means to be God. Anything that has a beginning, however exalted, is on the other side of that line. If the Son is begotten, then there was a point at which he was not, and to say otherwise is to have two unbegotten principles, which is to abandon the unity of God.

Arius did not conclude that the Son is a creature like other creatures. On his account the Son was brought into being before time and before everything else, is the agent through whom everything else was made, is unchangeable by grace, and is not to be counted among the works. But he is on the created side of the divide, and his knowledge of the Father is not the Father self-knowledge.

The evidential problem is serious and is worth stating plainly. Almost nothing by Arius survives except in the works of people refuting him. Two letters and fragments of a work in verse called the Thalia are the main texts, and the Thalia fragments come to us quoted by Athanasius, who was arguing against them. Historians reconstruct his position from that material with due caution, and the label Arian was applied by opponents to a much wider range of positions than he himself held.

The Council of Nicaea in 325 condemned the position and produced a creed confessing the Son as begotten and not made, and as homoousios, of one substance with the Father. The word was not an obvious choice. It is not scriptural, and a form of it had been rejected in an earlier condemnation, which is why many bishops who had no sympathy at all with Arius were uneasy about it.

That unease is why the council did not settle anything for sixty years. The decades that followed produced a spectrum rather than two camps: a party preferring homoiousios, of like substance, which wanted to affirm the Son divinity while avoiding a word suggesting the Father and Son are one thing; a homoian party content to say simply that the Son is like the Father, which had imperial backing for a period; and a group holding the Son to be unlike the Father, which was the sharpest form of the original position. Bishops were deposed and restored repeatedly as emperors changed.

The settlement came with the work of Athanasius and then the Cappadocian theologians, who supplied a vocabulary distinguishing one substance from three persons, and with the Council of Constantinople in 381. By then the mission of Ulfilas had carried a non-Nicene creed to the Goths, and the Germanic kingdoms established in the western empire, Visigothic, Ostrogothic, Vandal and Lombard, held it for generations. Historians now generally call that Homoian rather than Arian, since its content is not simply what Arius taught.