From 4 to 7 June 2025, a landmark event for the Christian world took place at the Pontifical University of St. Thomas Aquinas (Angelicum) in Rome — the international conference “Nicaea and the Church of the Third Millennium: Towards Unity between the Catholic and Orthodox Churches”. It was organised by the International Orthodox Theological Association (IOTA) in cooperation with the Angelicum Institute of Ecumenical Studies and brought together over 300 participants — theologians, hierarchs and clergy of the Orthodox, Roman Catholic, Protestant and Oriental Orthodox Churches.
The conference was dedicated to the 1700th anniversary of the Council of Nicaea, an event that laid the foundations of Christian orthodoxy and initiated the conciliar path of the Church. The focus was on whether the legacy of Nicaea can contribute to achieving greater unity among Christians today. Over the course of four days in Rome, more than 100 presentations were given by leading Orthodox, Catholic and Protestant theologians on the 1700th anniversary of the First Ecumenical Council, the Nicene Creed, its theological content and ecumenical potential.
Opening: prayer, teaching and singing in the spirit of Nicaea
The conference opened in an uplifting spiritual atmosphere. After an ecumenical prayer service, in which Cardinal Kurt Koch, Metropolitan Job of Pisidia, Bishop Cyril of Los Angeles and Archbishop Rowan Williams prayed together, the participants were welcomed by the rector of the Angelicum, Rev. Thomas Joseph White, O.P., the director of the Institute of Ecumenical Studies, Rev. Hyacinth Destivelle, O.P., and the president of IOTA, Professor Paul Gavryliuk.
In his speech, Paul Gavryliuk emphasised that the task of the conference was to identify how the legacy of the Council of Nicaea could become a source of hope and an impetus for deepening unity among Christian Churches: “Can Nicaea really change anything for church unity today? This is the central question we are asking during these days of theological dialogue”. According to him, it is not only about a historical event, but also about a challenge to contemporary Christianity: to place Christ, the Son of God, whom the Nicene Creed professes, at the center of common church life and theology.
Three key reports: Nicaea as a common point of reference
Cardinal Kurt Koch, President of the Pontifical Council for Promoting Christian Unity, called for a renewal of the common Christian vision of Jesus Christ, embodied in the Creed. He emphasised that the renewal of a living experience of faith in Christ is an urgent task of our time, which should be carried out in the spirit of ecumenism: “The essence of ecumenism lies in a common conversion to Christ”.
Metropolitan Job (Gecha) of Pisidia emphasised the universal character and timeless value of the Nicene Creed, which “transcends space and time”. In addition, he mentioned the achievements of inter-Christian dialogue, including the reinterpretation of the Filioque doctrine and the primacy of the Bishop of Rome. He also did not overlook the obstacles, including the date of Easter and mutual recognition of the sacraments, calling for their overcoming.
Rowan Williams, former Archbishop of Canterbury, gave an insightful presentation on how Nicene Christology reveals the very nature of God’s love. He reminded that the Trinity is not an abstract doctrine, but a revelation of this love, which is realised in the Incarnation of Christ. “The unity of the Church must be rooted in that eternal capacity of God for self-giving, which Nicaea professes”, he said.
It is worth mentioning the participants from Ukraine, in particular the report by Archimandrite Cyril (Hovorun), which received wide resonance. In his report “The Council of Nicaea and its significance for Orthodox-Catholic relations”, he highlighted the historical perspectives of mutual recognition between Orthodoxy and Catholicism, analysed the contemporary significance of Filioque and examples of mutual acceptance of Christian baptisms, and emphasised the potential of the Nicene Creed for practical dialogue based on the principles of the 21st century. His presentation sparked a lively discussion, which also addressed topics related to Trinitarian and other dogmatic issues in the context of Christian unity.
Main topics: dogma, conciliarity, Holy Easter
The conference programme covered a wide range of topics, from Trinitarian and Christological dogmatics to practical and canonical issues concerning synodality, primacy, autocephaly, the date of Easter celebrations, and ecumenical models of unity. Speakers included renowned theologians from Oxford, Cambridge, Paris, Athens, Rome, Washington, and elsewhere.
Plenary and sectional sessions explored the legacy of Nicaea in terms of liturgy, canon law, patristics, interchurch dialogue, and contemporary culture. One of the key discussions was the issue of harmonising the date of Easter celebrations — a question that is not only symbolic but also potentially practical for bringing the Churches closer together.
A shared song of faith — a sign of hope
The programme also included musical interludes featuring choirs representing Dominican, Coptic, Romanian and Ukrainian traditions. These renditions of the Creed were not merely decorative elements of the event, but a living manifestation of spiritual unity in the confession of the One Lord. While in 325 the Council of Nicaea was the Church’s response to the challenges of that time, then 1,700 years later its voice rang out again — this time as a hope for overcoming division and restoring common Communion.
The conference ended with a private audience with Pope Leo XIV in the Sala Clementina. The IOTA delegation, led by Paul Gavryliuk, presented the pontiff with commemorative souvenirs. The Pope addressed those present with the following words: “Remember that the unity to which Christians aspire is not the fruit of our labour, but a gift given by the Holy Spirit”. The meeting with the Pope demonstrated the Catholic Church’s highest level of interest in ecumenical dialogue, the foundations of which were laid in Nicaea 1.700 years ago.
Conclusion
This conference became a true theological temple of dialogue — a place where the historical heritage of the Council of Nicaea was combined with contemporary spiritual challenges. Thanks to presentations and powerful discussions on Trinitarian and Christological issues of the past and present, synodality and primacy, autocephaly and schism, liturgical practices and iconography, and finally on the celebration of Easter, a real foundation has been laid for practical steps to deepen Christian unity.
The conference in Rome was not only an anniversary event, but also a true theological laboratory. Here, Nicaea appeared not as an archaic council of the fourth century, but as a modern inspiration for a new Christian millennium. At a time when the world is divided, Christians have a unique opportunity to bear witness to their unity of faith and love for Christ, “consubstantial with the Father”. And it is precisely this witness that is perhaps the strongest sign from Christians for the world today.
General information about the conference is available on the IOTA website, including a press release posted here: https://iota-web.org/2025-conference-press-releases/
