This Wikipedia photo shows a depiction of the First Council of Nicea

On May 20, 325 A.D., the Roman Emperor Constantine opened the First Council of Nicaea. The first ecumenical council of the Christian Church, the meeting addressed several key topics among early Christians, including the divisive issue of Arian Christianity.

Throughout the second and third centuries A.D., the Christian Church had been spreading steadily within the Roman Empire. There are several reasons why Romans turned to Christianity at this time. Roman culture and society had always been highly class conscious, and Christianity offered an equality that perhaps had never existed before in Rome. All men and women were brothers and sisters before Christ, regardless of social class. Indeed, the early church counted many women among its ranks of organizers and proselytizers.

Christianity also placed an emphasis upon charity, and Christian bishops often helped the poor and less fortunate in a way that seemed difficult for many Romans to comprehend. Of course, one cannot discount faith. Christ offered victory over death, something that the traditional Roman pagan religion, which worshiped the pantheon of Jupiter, Venus and others, never firmly promised.

The Christians of Rome suffered periods of persecution within the empire, the first under the reign of Nero in 64 A.D. when they were blamed for the great fire. Later persecutions either sprang up in various localities or were directed by the state. Romans resented that the Christians would not sacrifice to the traditional gods, particularly when as a form of military service. Also, many misunderstandings plagued relations between Christians and non-Christians. Many Romans believed that when Christians talked of eating the flesh and drinking the blood of Christ, they were practicing some form of cannibalism. The Christian practice of calling fellow churchgoers, even spouses, as “brother” and “sister” was interpreted as some form of incest.

A Roman general and religious pagan traditionalist, Constantine fought his civil war to win the imperial throne. Shortly before the Battle of the Milvian Bridge in 312 A.D., however, Constantine said that he had a vision in which he saw a cross and heard the words, “In this sign, you shall conquer.” Constantine won the battle and soon installed himself in Rome as emperor. He became a champion of Christian rights, though he himself would not be baptized until shortly before his death in 337 A.D. Under Constantine, the Christian Church, which had been at many times an underground organization, flourished and quickly became a major force within the empire.

The Christian Church was not a monolithic institution, however. Various factions and practices had taken root over the years, and Constantine saw the need for a unity of doctrine and a clearer organization for the church's hierarchy. There was also a critical issue that had already caused many problems within the church and threatened serious discord: the spread of Arianism.

In his book “Lost to the West: The Forgotten Byzantine Empire That Rescued Western Civilization,” historian Lars Brownworth wrote: “Just as the empire came together politically, however, a new and deadly heresy threatened to permanently rip it apart. It started in Egypt when a young priest named Arius started teaching that Christ was not fully divine and was therefore inferior to God the Father. Such a teaching struck at the heart of the Christian faith, denying its main tenet, which held that Christ was the incarnate word of God, but Arius was a brilliant speaker, and people began to flock to hear him speak. The church was caught completely off guard and threatened to splinter into fragments.”

With only sporadic, almost cell-like leadership throughout the empire, the traditionalist Christians could not rally to oppose the spread of Arius' teachings, and many began to follow his form of worship. Many scholars believe that Constantine himself took no formal position on the Arian heresy, he simply wanted unity and was willing to back whichever side looked best able to reach that end. A council of bishops was needed to formally decide this and other matters.

Brownworth wrote: “Announcing a great council, Constantine invited every bishop in the empire to attend, personally covering the cost of transportation and housing. When several hundred clerics had arrived at the city of Nicaea, the emperor packed them into the main cathedral and on May 20, 325, opened the proceedings with a dramatic plea for unity.”

The council first dealt with less important issues. The bishops addressed the problem of recognizing baptism performed by heretics, and then devised the formula for calculating the exact date of the year that Easter would fall upon. On the fundamental issue of Arianism, however, each faction stuck rigidly to its positions and refused any form of compromise.

In his book “How Rome Fell: Death of a Superpower,” historian Adrian Goldsworthy wrote: “Fierce debate raged over the precise nature of the Trinity — God the Father, God the Son, and the Holy Spirit. In many ways the arguments show the deep influence of the ways of thinking promoted by the major philosophical schools, with their obsession with specifically categorizing things. … Constantine was present but seems to have acted as an interested layman and did not actually take part in the debate.”

Among the bishops present was the staunch anti-Arian, St. Nicholas of Myrna, who was the basis for the Santa Claus legend. Tempers flared during the debate, and according to some accounts St. Nicholas even slapped Arius at one point. Eventually, the traditionalist faction won over the Arians, and a new creed was created. God the Father, Jesus Christ, and the Holy Spirit were described as “of the same substance.” The Greek word used was “homoousios.”

The Nicene Creed therefore completely rejected Arianism. Pro-Arian bishops, like Constantine's favorite Eusebius of Caesarea, were forced to recant and accept the Nicene Creed lest they be excommunicated. Many like Arius who refused to accept the Nicene Creed were sent into exile, though years later Constantine would allow them to return to their homes.

The First Council of Nicaea was significant for its role in early Christian Church organization and defining such concepts within the church as orthodoxy and heresy. It saw learned bishops coming from all over to decide these questions in a (relatively) democratic manner, and it also saw support from the emperor himself, giving the council a firm foundation of legitimacy.

Arian Christianity would not die out as a result of the council, however. Though most Romans ultimately embraced the Nicene Creed, Arian Christians remained a minority for years to come, and even some later emperors would worship as Arian Christians. Arian Christianity would also spread to the German lands north of the empire, and when the Goths invaded in the late fourth century, they did so as Arians. By the time the Western Roman Empire fell in A.D. 476, the various Germanic kingdoms that arose were almost all Arian, ruling over a population of largely Roman Catholic subjects. Arianism would virtually disappear in the West, however, after the Frankish King Clovis I converted to Catholicism in the late fifth century and after the Muslim invasion of Visigothic Spain in A.D. 711.

Cody K. Carlson holds a master's degree in history from the University of Utah and teaches at Salt Lake Community College. He is also the co-developer of the History Challenge iPhone/iPad apps. Email: