The Council of Nicaea 1,700 years ago recognized that Christian unity had to be based on a common faith and should be demonstrated by a common celebration of Easter, the most sacred feast of the Christian year, said speakers at a Rome conference.
Newsroom (06/06/2025 08:30 , Gaudium Press) As the Christian world marks the 1,700th anniversary of the Council of Nicaea, a pivotal moment in the history of Christianity, a conference in Rome has reignited discussions on the council’s enduring legacy of fostering unity through a shared profession of faith and the urgent need for a unified Easter celebration.
Held from June 4-7, the event was co-organized by the International Orthodox Theological Association and the Institute for Ecumenical Studies at Rome’s Pontifical University of St. Thomas Aquinas, with support from the Vatican’s Dicastery for Promoting Christian Unity. The gathering brought together theologians, bishops, and ecumenical leaders to reflect on Nicaea’s contributions and its relevance to modern challenges in Christian unity.
The Council of Nicaea, convened in 325 AD under Emperor Constantine, was a landmark event that produced the Nicene Creed, a foundational statement of Christian belief, and established a formula for determining the date of Easter, the faith’s most sacred feast. Yet, as speakers noted, while the Creed remains a unifying force across denominations, divisions persist, particularly in the celebration of Easter, due to differing liturgical calendars. The conference, coinciding with the election of Pope Leo XIV, whose episcopal motto, “In Illo uno unum” (“In the One [Christ], we are one”), draws from St. Augustine, underscored a renewed commitment to ecumenism and synodality.
Nicaea’s Enduring Legacy
Paul L. Gavrilyuk, president of the International Orthodox Theological Association and Aquinas Chair in Theology and Philosophy at the University of St. Thomas in St. Paul, Minnesota, described the Council of Nicaea as a “landmark exercise in collective truth seeking and discernment.” He highlighted its “enduring and universally significant dogmatic outcome” enshrined in the Nicene-Constantinopolitan Creed, which continues to serve as a touchstone for orthodox Christian belief. “The Creed is not just a liturgical text but a living statement of faith that unites Christians across time,” Gavrilyuk said, noting its role in bridging denominational divides.
Cardinal Kurt Koch, prefect of the Dicastery for Promoting Christian Unity, echoed this sentiment, calling the Nicene Creed “the strongest ecumenical bond of the Christian faith.” He emphasized its unique position as a shared confession, predating the schisms that later fragmented Christianity. “The Council of Nicaea occurred when Christianity was still largely unified; its Creed unites all Christian churches and ecclesial communities to this day,” Koch said. He noted that approximately 318 of the 1,800 bishops of the time participated in the council, engaging in a synodal process of shared reflection to articulate core doctrines, particularly the divinity of Christ.
Orthodox Metropolitan Job of Pisidia, a theologian and co-chair of the Catholic-Orthodox theological dialogue, presented Nicaea as a model for contemporary ecumenism. He argued that the council balanced the need for agreement on essential doctrines with flexibility on secondary matters. “The Nicene Creed transcends the limits of time and space,” he said, noting its integration into Christian liturgy by the turn of the sixth century as a universal confession of faith received from Christ through the apostles.
The Challenge of a Common Easter
A central focus of the conference was the persistent challenge of aligning Easter celebrations, a goal set by Nicaea but disrupted by later historical developments. The council established that Easter should be celebrated on the first Sunday after the full moon following the spring equinox, a formula based on astronomical phenomena rather than a specific calendar. However, the adoption of the Gregorian calendar by Western Christians in 1582, while Eastern Christians continued using the Julian calendar, has resulted in divergent Easter dates, with rare coincidences.
Metropolitan Job highlighted ongoing discussions within Orthodox churches to adopt more accurate astronomical data, using the meridian of Jerusalem—where Christ’s death and resurrection occurred—as a reference point. He noted that such proposals have been postponed multiple times, reflecting the complexity of achieving consensus. Cardinal Koch reaffirmed the Catholic Church’s openness since the 1960s to a common Easter date, provided all Christian churches agree. “A shared celebration of Easter is a pressing pastoral concern, especially for interdenominational families and in an era of global mobility,” Koch said. He added that a unified Easter would strengthen the Christian witness, as “Easter is not only the oldest but the central and most important feast of Christianity.”
Synodality and Ecumenical Learning
The conference also emphasized Nicaea’s synodal approach as a model for modern ecumenism. Cardinal Koch described the Creed as the “expression of a synodal struggle” among bishops to formulate an orthodox and worshipful statement of faith. He called for a renewed commitment to synodality—shared listening, reflection, and discernment—urging churches to learn from each other’s synodal structures. “The restoration of church unity requires agreement on the essential content of the Christian faith, in continuity with its apostolic origins,” he said.
This call for synodality resonated with Pope Leo XIV’s broader vision for the Church, as seen in his recent address to lay associations, where he emphasized unity and mission. The alignment of the Nicaea anniversary with his election was noted as providential, with his motto reflecting St. Augustine’s vision of unity in Christ.
A Deeper Call to Faith
Anglican Archbishop Rowan Williams, former archbishop of Canterbury, offered a theological reflection on the Creed’s role in fostering deeper faith and unity. He described the Creed as an expression of belief in the Trinity, which animates the Church as the body of Christ. “The unity of the church is neither a human achievement nor a static identity but a dynamic movement between subjects, bringing one another alive in the life of the eternal Son,” Williams said. He urged Christians to see the Nicaea anniversary as a call to live out the Creed’s truths in community and mission.
Gavrilyuk added that the Creed’s ecumenical significance lies in its ability to anchor Christians in a shared faith while allowing for diversity in practice. “Nicaea shows us that unity does not mean uniformity but a shared commitment to the essentials,” he said, encouraging dialogue to bridge historical divisions.
Looking Forward
The Rome conference seeks towards a renewed commitment to ecumenical dialogue, inspired by Nicaea’s example of collective discernment. Speakers called for practical steps toward unity, including ongoing efforts to align Easter celebrations and deepen synodal collaboration. Cardinal Koch emphasized that a unified Easter would not only resolve pastoral challenges but also enhance the credibility of the Christian message in a divided world.
- Raju Hasmukh with files from UCA News
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