Pope Leo XIV addressed a conference on June 7, 2025, marking the 1,700th anniversary of the Council of Nicaea. The event was organized by Œcumenicum — the Institute for Ecumenical Studies of the Angelicum — and the International Orthodox Theological Association. Pope Leo XIV extended a special greeting to representatives from the Orthodox and Oriental Orthodox Churches.
During his address, Pope Leo XIV expressed his apologies for being late and acknowledged that he is still adapting to his new role as Pontiff. He emphasized that the Symposium's focus on future unity between Catholics and Orthodox Christians aligns with the foundational work of the First Ecumenical Council.
The Pope highlighted three themes of the Symposium: faith, synodality, and the date of Easter. He noted that "the year 2025 represents 'an invaluable opportunity to emphasise that what we have in common is much stronger... than what divides us.'" He stressed that returning to the teachings of Nicaea could help bridge theological differences.
Regarding synodality, Pope Leo XIV mentioned its importance in addressing theological and canonical questions at a universal level. He referenced recent ecumenical dialogues as crucial for understanding synodality within Church unity.
On the topic of Easter's date, he pointed out that differing calendars have led to disunity among Christians during this significant feast. The Pope reaffirmed "the openness of the Catholic Church to the pursuit of an ecumenical solution" for a unified celebration.
Concluding his address on Pentecost's eve, Pope Leo XIV called for unity as a divine gift rather than solely human effort. He invited attendees to pray together using a prayer from Eastern tradition:
"O Heavenly King, the Comforter, the Spirit of Truth,
Who art everywhere and fillest all things;
Treasury of Blessings, and Giver of Life,
Come and abide in us, and cleanse us from every impurity,
and save our souls, O Good One." Amen.
He ended with a blessing: "The Lord be with you. The blessing of Almighty God, the Father, the Son, and the Holy Spirit come upon you and remain with you forever."