Arianism

Arianism

Main article: Arianism

Arianism, declared by the Council of Nicaea to be heresy, denied the full divinity of Jesus Christ, and is so called after its leader Arius.^[23] It has been called the most challenging heresy in the history of the Church.^[24]

Arius, born probably in Libya between c. 260 and 280, was ordained a priest in Alexandria in 312–313. Under Bishop Alexander (313-326), probably in about 319, he came forward as a champion of subordinationist teaching about the person of Christ.^[25]

Arius appears to have held that the "Son of God" was not eternal but created by the Father as an instrument for creating the world and therefore not God by nature, different from other creatures in being the one direct creation of God.^[23] The controversy quickly spread, with Arius seeking support from other disciples of his teacher Lucian of Antioch, notably Eusebius of Nicomedia, while a local synod under Alexander excommunicated Arius.^[25] Because of the agitation aroused by the dispute,^[23] Emperor Constantine I sent Hosius of Córdoba to Alexandria to attempt a settlement; but the mission failed.^[25] Accordingly, in 325, Constantine convened the First Council of Nicaea, which, largely through the influence of Athanasius of Alexandria, then a deacon but destined to be Alexander's successor, defined the co-eternity and coequality of the Father and the Son, using the now famous term "homoousios" to express the oneness of their being, while Arius and some bishops who supported him, including Eusebius, were banished.^[23]

This council marks the end of the Early Christian period and the beginning of the period of the First seven Ecumenical Councils.