In the first three centuries, the church found itself in a hostile environment. On the one hand, it grappled with the challenge of relating the language of the gospel, developed in a Hebraic and Jewish-Christian context, to a Graeco-Roman world. On the other hand, it was threatened not only by persecution, but also by ideas that were in conflict with the biblical witness.
In A.D. 312, Constantine won control of the Roman Empire in the battle of Milvian Bridge. Attributing his victory to the intervention of Jesus Christ, he elevated Christianity to favored status in the empire. "One God, one Lord, one faith, one church, one empire, one emperor" became his motto.
The new emperor soon discovered that "one faith and one church" were fractured by theological disputes, especially conflicting understandings of the nature of Christ, long a point of controversy. Arius, a priest of the church in Alexandria, asserted that the divine Christ, the Word through whom all things have their existence, was created by God before the beginning of time. Therefore, the divinity of Christ was similar to the divinity of God, but not of the same essence. Arius was opposed by the bishop, Alexander, together with his associate and successor, Athanasius. They affirmed that the divinity of Christ, the Son, is of the same substance as the divinity of God, the Father. To hold otherwise they said, was to open the possibility of polytheism, and to imply that knowledge of God in Christ was not final knowledge of God.
To counter a widening rift within the church, Constantine convened a council in Nicaea in A.D. 325. A creed reflecting the position of Alexander and Athanasius was written and signed by a majority of the bishops. Nevertheless, the two parties continued to battle each other. In A.D. 381, a second council met in Constantinople. It adopted a revised and expanded form of the A.D. 325 creed, now known as the Nicene Creed.
The Nicene Creed is the most ecumenical of the creeds. The Presbyterian Church (U.S.A.) joins with Eastern Orthodox, Roman Catholic, and most Protestant churches in affirming it. Nevertheless, in contrast to Easter Orthodox churches, the western churches state that the Holy Spirit proceeds not only from the Father, but from the Father and the Son (Latin, filioque). To the eastern churches, saying that the Holy Spirit proceeds from both the Father and the Son threatens the distinctiveness of the person of the Holy Spirit; to the western churches, the filioque guards the unity of the triune God. This issue remains unresolved in the ecumenical dialogue.