The First Ecumenical Council of Nicea: Celebrating 1700 Years of Nicene Faith

The Church Councils you need to know, and why you need to know them

This year (2025) marks the historic 1700th anniversary of the First Ecumenical Council of Nicaea (AD 325), where 318 Holy Fathers gathered to defend the true faith against heresy. Under the reign of Emperor Constantine the Great, these courageous bishops articulated the basic truths of our Orthodox Christian faith, particularly the divinity of Christ and His unity and consubstantiality with the Father.

The Council's enduring legacy lives on in the Nicene Creed, which we proclaim at every Divine Liturgy. This Symbol of Faith powerfully declares that our Lord Jesus Christ is “Light of Light, true God of true God, begotten, not made, of one essence with the Father.” The Holy Fathers' inspired work continues to guide our worship and theological understanding to this day.

As we commemorate the Sunday of the Fathers of the First Ecumenical Council this week, we give thanks to God for their steadfast defense of Orthodox truth. Their example reminds us to remain vigilant in preserving and living out the apostolic faith they so carefully articulated.

At Saint Mark Greek Orthodox Church (Boca Raton, Florida) we not only invited all faithful to join us in celebrating this momentous anniversary and these pillars of Orthodoxy through the appointed prayers and readings in the service, but also by receiving a Nicea icon card as they left the temple. We will be hosting a four week study on the council of Nicea featuring our clergy and catechist (me!) in August.

The above was adapted from the worship guide for June 1, 2025 at Saint Mark Greek Orthodox Church, Boca Raton, Florida—Jamey Bennett is the author of both versions.

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Father Mark Leondis spoke for a few minutes on the subject of the Ecumenical Councils during our “What We Believe” section of the service, shortly before the sermon:

After that, I had the unique opportunity (for a Reader!) to give a short homily focused specifically on the First Council of Nicea, and its significance in the life and beliefs of the Orthodox Christian. Here’s a video of that sermon (followed by the text):

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Homily for the Sunday of the Holy Fathers of the First Ecumenical Council

by Reader James Bennett

In the name of the Father, and of the Son, and of the Holy Spirit. Amen.

Today is the Sunday of the Holy Fathers of the First Ecumenical Council—and as we celebrate this Holy Day today, we commemorate 1700 years since that First Council. The year was AD 325, and the Church faced its first major doctrinal crisis in Nicea, located in modern-day Turkey. A priest named Arius was teaching that Christ was created—"there was a time when He was not,” he claimed.

But this teaching directly contradicted Scripture and the teachings of the God-bearing Fathers. St. John's Gospel opens with “In the beginning was the Word, and the Word was with God, and the Word was God” (John 1:1). Christ Himself declared, “I and the Father are one” (John 10:30). These weren't ambiguous statements—they were clear declarations of Christ's divinity. The 318 Holy Fathers who gathered weren't creating new theology. They were articulating what the Church had always believed, but with renewed precision.

The readings appointed for this feast day are from Acts 20 and John 17. Inspired by Christ's prayer in John 17:11, “that they may be one, as we are one," and much like Saint Paul exhorting the Ephesian elders in Acts 20 to "feed the church of God, which he has purchased with his own blood,” the Nicene Fathers acted as divinely inspired shepherds guarding the flock from the Arian heresy. Recognizing the threat of those who, as Paul warned in Acts 20, would “draw away disciples after them,” they refuted Arius’ denial of Christ's full divinity, affirming Christ as “God from God, Light from Light, true God from true God, begotten, not made, of one essence with the Father.”

The unity Christ Himself prayed for entails a commitment to truth. The Fathers tirelessly preserved this unity within the Church, mirroring the divine Trinity, ensuring the faithful receive spiritual nourishment of true faith. The hymns of the Church praise them as “luminaries upon the earth” guiding us to true faith—and the Kontakion hymn says the Church was “strengthened into one faith through the preaching of the Apostles and the doctrines of the Fathers.”

The term homoousios—“of one essence” with the Father—became central to Orthodox teaching. It means Christ shares the same divine nature as God the Father. He isn't created or adopted, but eternally begotten. This wasn't just philosophical wordplay—it was a precise expression of the revealed truth about our Lord God and Savior Jesus Christ.

Even our understanding of theosis—our potential for holiness and deification in Christ—depends on, and is only possible because of, Christ being fully God. As St. Athanasius explained, “God became man so that man might become god.”

St. Athanasius, who was present at that Council as a young deacon, would spend much of his life defending these truths. But the Arian controversy didn't end at Nicea—it continued for decades. St. Athanasius was exiled five times for his defense of the Nicene faith and his opposition to Arianism. These exiles spanned multiple years and were ordered by various Roman emperors. But the Council established the benchmark of Orthodox teaching that would eventually prevail.

The Creed we say every Sunday was completed at the Council of Constantinople in AD 381, but the bulk of it comes directly from Nicea.

Nicea gave us three essential elements:

1. The foundational text of the Nicene Creed

2. A clear articulation of Christ's divinity, consubstantiality with Giod the Father, and eternal existence

3. A model for defending Orthodox truth

When we proclaim the Creed, we stand in an unbroken chain with those Holy Fathers who defended the truth of Christ's divinity, and the many generations of Orthodox Christians through the centuries who continued to affirm this truth. Their words aren't merely historical artifacts—they are the very heartbeat of our Orthodox faith, as vital and necessary now as they were 1700 years ago. Every time we declare Christ as "Light of Light, true God of true God," we affirm their triumph and participate in this living, eternal truth.

Brothers and sisters in Christ, the faith of the Holy Fathers is not just history—it is our inheritance, the fullness of divine revelation, but the question is: Have we made it our own? The Creed we proclaim isn't merely words; it is a declaration of truth, a proclamation that calls us to live in the light of Christ's divine ands human natures every day. The Fathers stood firm so that we might stand firm in this faith too—we are called to stand firm by living it in our lives. We are called to embrace this faith personally and boldly, allowing it to transform us and make us witnesses in this world of Christ's endless love.

Make this faith your own—for the creed may describe what we all believe, but it begins with “I believe…”

“This is the Apostolic Faith, this is the Orthodox Faith, this is the Faith of the Fathers, this is the Faith that has established the Universe!” Amen.