The First Ecumenical Council: Doctrinal Identity and Enduring Significance, 1700 Years Later

by Fr. Panagiotis Kapodistrias, 

Protopresbyter of the Ecumenical Throne

This year marks 1700 years since the convocation of the First Ecumenical Council in Nicaea of Bithynia in 325 AD—an anniversary that invites a renewed reflection on one of the most defining events in the life of the Church. The Council stands as a foundational synodal moment, combining theological clarity, institutional cohesion, and canonical maturity, shaping the Church from the post-Constantinian era to our own times.

Convened at the initiative of Emperor Constantine the Great—later canonized as Saint Equal-to-the-Apostles—the Council’s primary purpose was to address the theological implications of Arianism, as promoted by Arius, a presbyter from Alexandria. Arius claimed that the Son was neither co-eternal nor consubstantial with the Father but a created being—albeit superior to all creation. This position undermined the unity of the Holy Trinity and compromised the very basis of Christian soteriology.

The Council’s response was both resolute and precise. It affirmed the full divinity of the Son with the now-iconic formulation: “True God from true God, begotten not made, consubstantial (homoousios) with the Father.” Though the term homoousios does not originate in the biblical lexicon, its inclusion was essential to safeguard theological clarity and uphold the apostolic tradition, echoing the exhortation of the Epistle of Jude: “Contend for the faith that was once for all entrusted to the saints” (Jude 3).

Saint Athanasius the Great, who attended the Council as a deacon, later emphasized in his works the salvific necessity of this doctrine. In his Against the Arians (PG 26, 141C), he articulates the now-classic patristic axiom: “What was not assumed is not healed.” The incarnate Word—as declared in the Gospel of John (1:3), “All things came into being through Him”—affirms both the creative and redemptive character of divine revelation.

Beyond doctrinal definition, the Council also issued canonical regulations with ecclesiological and liturgical implications. Notably, it resolved to fix a unified date for the celebration of Pascha, independent of the Jewish calendar—a move aimed at fostering liturgical unity within the Church. Constantine himself communicated this decision in a letter to the Churches (Vita Constantini III, 20; PG 20).

Eusebius of Caesarea, a contemporary and eyewitness to the events, offers valuable testimony in his historical works (Ecclesiastical History X, 5; Life of Constantine), highlighting both the breadth of participation and the theological rigor of the Council. He affirms the Fathers’ commitment to expressing a unified confession of faith rooted in ecclesial tradition.

The significance of the First Ecumenical Council transcends its historical moment. Its Christological confession of the Son’s consubstantiality with the Father remains vital to the Church’s theology and worship. This truth stands as a structural pillar of the faith, immune to the fluctuations of history and culture.

Academically, the Council continues to offer a rich field for research: from the distinction between ousia (essence) and hypostasis (person), to the appropriation of philosophical language in theology, the interplay of imperial authority and ecclesiastical deliberation in Constantine’s time, and the Council’s enduring influence on subsequent Ecumenical Synods. The acts of the Council and the writings of the Fathers remain indispensable primary sources for theological and historical inquiry.

The First Ecumenical Council retains a living place in the Church’s life. Its unwavering doctrinal confession, pastoral concern for unity, and responsible synodal action form a coherent model of conciliarity. The decision on homoousios is not only a doctrinal assertion—it expresses the heart of the Christian experience of salvation. The spirit of this path is well captured in the exhortation of the Apostle Peter: “Therefore be serious and watchful in your prayers” (1 Peter 4:7).

The Council of Nicaea affirms a faith that is unified, enduring, incorruptible, and unalterable. Its doctrinal lucidity and ecclesiological integrity provide firm ground for theological reflection and for the Church’s perennial mission. The 1700-year anniversary invites the modern believer and thinker alike into a deeper theological engagement and renewed fidelity to the apostolic tradition. May we all draw creatively from its witness—so that Orthodoxy may ever become Orthopraxy.