Ahead of his Apostolic Journey to Türkiye, Pope Leo XIV has released a new Apostolic Letter titled In unitate fidei (“In the Unity of Faith”) to commemorate the 1700th anniversary of the First Council of Nicaea. The letter, published on Nov. 23, the Solemnity of Christ the King, invites the global Church to renew its commitment to the profession of faith expressed in the Nicene Creed.
The Catholic Church is marking 1,700 years since the historic Council convened in 325 AD by Emperor Constantine, where Christian bishops formulated the foundational Creed affirming the divinity of Jesus Christ. Pope Leo’s upcoming journey will take him to Ankara, Istanbul, and İznik—the ancient city of Nicaea—where the first ecumenical council took place.
In the 12-point Apostolic Letter, Pope Leo emphasizes that unity remains central to the Christian faith. He recalls that from the earliest centuries, believers have been called to “walk in harmony,” safeguarding the truth handed down through the Creed: “I believe in one Lord Jesus Christ… for our salvation he came down from heaven.”
The Pope highlights that the Nicene Creed remains a shared spiritual heritage for Christians worldwide. In this Holy Year dedicated to “Christ our Hope,” he describes the anniversary as a providential moment to focus on the heart of Christian belief: faith in Jesus Christ, Son of God.
In a world marked by war, fear, injustice, and humanitarian crises, he says, the Creed “gives us hope.”
Pope Leo also underscores the Council’s ongoing ecumenical relevance. While full unity among Christian Churches has not yet been achieved, he notes that decades of dialogue—grounded in one Baptism and the Nicene-Constantinopolitan Creed—have helped Christians recognize each other as brothers and sisters in Christ.
“What unites us is much greater than what divides us,” he affirms.
He stresses that in a divided world, a united Christian witness can become “a sign of peace and an instrument of reconciliation.” He also recalls the shared witness of Christian martyrs across denominations, whose blood “unites us and urges us toward peace.”
Looking ahead, Pope Leo encourages Christians to walk together in an ecumenism that does not retreat into the past nor settle for division, but seeks future reconciliation through dialogue and shared spiritual gifts. The Nicene Creed, he says, offers “a model of true unity in legitimate diversity.”
The letter concludes with a call to prayer: an invitation for all Christians to invoke the Holy Spirit to guide the journey toward deeper unity and renewed faith.
Credit: Vatican News
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