Council of Nicaea – Fideograph.com

Section I

The Crisis that summoned Council of Nicaea

The apologetic argument: The Council of Nicaea uses the word homoousios — of the same substance — a term not found anywhere in Scripture. This single fact permanently refutes Sola Scriptura: the most important doctrinal definition in Christian history was made by the Church's teaching authority using a non-scriptural term. Every Christian who confesses the Nicene Creed has already, in that act, acknowledged that the Church has authority to define doctrine beyond the explicit words of Scripture.

The Council of Nicaea was convened by Emperor Constantine I in May AD 325 in Nicaea, Bithynia (modern Iznik, Turkey). It was the first ecumenical council of the Church — the first time bishops from across the entire Christian world gathered to define doctrine with binding authority. Around 318 bishops attended, predominantly from the Eastern churches, though Pope Sylvester I sent two presbyters as his legates.

The immediate occasion was the Arian controversy. Arius, a priest of Alexandria, had been teaching that the Son of God was a creature — the first and greatest of God’s creations, but not co-eternal and co-equal with the Father. His formula the Son had a beginning had spread rapidly through the Eastern church, threatening to split Christianity into two irreconcilable camps.

The Council condemned Arianism and defined that the Son is homoousios — of the same substance — as the Father. This single word, not found in Scripture, became the test of orthodoxy. Its adoption is itself a decisive argument against Sola Scriptura: the most important doctrinal definition in Christian history uses a term the Bible does not contain, chosen by the Church’s teaching authority to express what Scripture implies.

Section II

The Creed Defined

Defined at Council of Nicaea

We believe in one God, the Father Almighty, maker of all things visible and invisible.

And in one Lord Jesus Christ, the Son of God, begotten of the Father [the only-begotten; that is, of the essence of the Father, God of God], Light of Light, very God of very God, begotten, not made, being of one substance (homoousios) with the Father; by whom all things were made [both in heaven and on earth]; who for us men, and for our salvation, came down and was incarnate and was made man; he suffered, and the third day he rose again, ascended into heaven; from thence he shall come to judge the quick and the dead.

And in the Holy Ghost.

[But those who say: "There was a time when he was not;" and "He was not before he was made;" and "He was made out of nothing," or "He is of another substance" or "essence," or "The Son of God is created," or "changeable," or "alterable" — they are condemned by the holy catholic and apostolic Church.]

Section III

Key Canons

Click any canon to expand the full text, commentary, and apologetic significance.

Canon 6

The Primacy of Alexandria, Rome, and Antioch

Jurisdiction

Let the ancient customs in Egypt, Libya and Pentapolis prevail, that the Bishop of Alexandria have jurisdiction in all these, since the like is customary for the Bishop of Rome also. Likewise in Antioch and the other provinces, let the churches retain their privileges.

Canon 6 confirms that the Bishop of Rome's special jurisdiction over the West is the model and precedent for the Bishop of Alexandria's jurisdiction over Egypt. The Roman arrangement is taken as the established norm. This canon was cited repeatedly in later councils as confirmation of Roman primacy.

Apologetic Significance The Council of Nicaea, citing Roman jurisdiction as the established precedent, confirms that Rome's authority over the Western churches was not a later innovation but an existing reality recognised by the universal Church in AD 325.

Canon 7

The Honour of the Bishop of Jerusalem

Precedence

Since custom and ancient tradition have prevailed that the Bishop of Aelia [Jerusalem] should be honoured, let him, saving its due dignity to the Metropolitian, have the next place of honour.

Jerusalem receives honorary precedence as the mother church of Christianity — but the canon carefully subordinates this to the metropolitan structure, preserving the existing order of authority.

Apologetic Significance Shows the Council operating with a clear theology of ecclesiastical rank and precedence — not a flat equality of all bishops, but a structured hierarchy with Rome at its head.

Canon 19

The Rebaptism of Paulianists

Sacraments

Concerning the Paulianists who have flocked to the Catholic Church, it is decreed that they must by all means be rebaptised.

The followers of Paul of Samosata, who had denied the full divinity of Christ, must be rebaptised because their original baptism was administered in a defective Trinitarian faith.

Apologetic Significance The Council's ruling on rebaptism confirms the Catholic theology of valid versus invalid baptism — a sacrament requires proper form, matter, and intention. The validity of baptism is not automatic.

Canon 20

No Kneeling on Sunday

Liturgy

Since there are some who kneel on the Lord's Day and in the days of Pentecost, the holy synod has decided that prayers should be offered to God while standing.

Standing on Sundays is a sign of the resurrection — the Church prays standing to represent the risen life. This ancient liturgical discipline reflects the theology of Sunday as the day of resurrection.

Apologetic Significance Even this apparently minor canon shows the Council exercising authority over liturgical practice across the universal Church — consistent with the ecclesiology of visible, institutional unity.

Section IV

Key Figures

AA

Athanasius of Alexandria

Deacon and secretary to Bishop Alexander; defender of homoousios at the Council; later Bishop of Alexandria and champion of Nicene orthodoxy for fifty years

Catholic — Defender of Nicaea

Ar

Arius of Alexandria

Presbyter of Alexandria whose teaching that the Son was a creature precipitated the Council. Condemned and exiled.

Condemned Heretic

HC

Hosius of Córdoba

Bishop of Córdoba and personal theological advisor to Emperor Constantine. Presided over the Council as papal legate of Pope Sylvester I.

Papal Legate — President of the Council

EC

Eusebius of Caesarea

The father of Church history and biographer of Constantine. Initially sympathetic to Arian-leaning positions but ultimately signed the Nicene definition.

Catholic — Semi-Arian sympathiser, ultimately orthodox

NM

Nicholas of Myra

Bishop of Myra in Lycia (modern Turkey). Tradition records him striking Arius in the face during the debates. Later venerated as Saint Nicholas.

Catholic — Defender of Nicaea

CI

Emperor Constantine I

Convoked the Council and presided over its opening sessions. Enforced the Nicene decision by imperial authority — exiling those who refused to sign.

Imperial Authority — Convener

The Ecumenical Councils