From Friday to Sunday, November 28 to November 30, 2025, two major events took place in Nicaea of Bithynia and in Constantinople.

First, commemorative events were held on the occasion of the historic 1,700th anniversary of the convocation of the First Ecumenical Council in Nicaea in Bithynia (325 AD). His All-Holiness Ecumenical Patriarch Bartholomew invited the heads of all Christian Churches to this historic occasion. The invitation was accepted by Pope Leo XIV of Rome and many other heads or representatives of Churches.

Second, on Saturday afternoon and Sunday morning, Pope Leo visited the seat of the Ecumenical Patriarchate at the Phanar for the great feast of Saint Andrew, the First-Called Apostle, during which the Ecumenical Patriarchate celebrates its thronal feast.

The two Primates signed a Joint Declaration in favor of peace in the world and the unity of the Churches. During their addresses, both Pope Leo and Ecumenical Patriarch Bartholomew presented a message of unity. The Ecumenical Patriarch emphasized that “the Nicene Creed acts like a seed for the whole of our Christian existence. Having the fervor of the faith of Nicaea burning in our hearts, ‘let us run the course’ of Christian unity ‘that is set before us.’” He then added that “despite so many intervening centuries, and all the upheavals, difficulties, and divisions they have created, we nevertheless approach this sacred commemoration with shared reverence and a common feeling of hope,” and stressed that “Nicaea derives from the Greek word for victory,” but not as “force and domination,” rather, “the unconquerable sign of the Cross”; it is “a victory not of this world,” but “a heavenly and spiritual victory… Let us love one another.”

For his part, the Primate of the Roman Catholic Church stressed that we must “overcome the scandal of the divisions,” that all Christians believe “in one Lord Jesus Christ,” and “in the one Christ we are one,” and that “we must strongly reject the use of religion for justifying war, violence, or any form of fundamentalism or fanaticism. Instead, the paths to follow are those of fraternal encounter, dialogue and cooperation.