IZNIK – During a visit to Iznik on Friday, Pope Leo issued a call for Christian unity and fraternity in a world rife with war and condemned fundamentalist attitudes and the use of religion to justify violence.

“Today, the whole of humanity afflicted by violence and conflict is crying out for reconciliation,” the pope said during a Nov. 28 ecumenical prayer service near the excavation site of the ancient Basilica of Saint Neophytos.

He made the remarks during an afternoon visit to Iznik, formerly Nicaea, in Turkey, to commemorate the 1700th anniversary of the Council of Nicaea, which reaffirmed Jesus’s divinity and produced the modern-day “Nicene Creed” recited during Sunday Masses.

Leo in his homily for the occasion said the desire for full communion among Christians goes hand in hand with “the search for fraternity among all human beings.”

“In the Nicene Creed, we profess our faith ‘in one God, the Father.’ Yet, it would not be possible to invoke God as Father if we refused to recognize as brothers and sisters all other men and women, who are created in the image of God,” he said.

Pope Leo insisted that humanity shares “a universal fraternity of men and women regardless of ethnicity, nationality, religion or personal perspectives.”

“Religions, by their very nature, are repositories of this truth and should encourage individuals, groups and peoples to recognize this and put it into practice,” he said.

In this regard, Leo issued condemned 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,” he said.

The rebuke of using religion to justify war is something that can be applied to Islamic fundamentalism and extremist violence, but also Russian Patriarch Kirill of Moscow’s justification of Russia’s invasion of Ukraine on grounds that it is a defense of traditional values against Western secularism.

Notably, while representatives of the various Christian confessions present in the region – Catholic, Protestant, and Orthodox – attended Friday’s prayer service, there was no one from the Patriarchate of Moscow, the largest Orthodox church in the world.

While the Patriarchate of Constantinople, headquartered in Istanbul, is considered primus inter pares, the “first among equals” in the Orthodox world, it is not the largest, numbering just 5.5 million members worldwide, compared to the roughly 110 million strong Russian Orthodox Church.

The Patriarchate of Constantinople, generally seen by the Russian patriarchate as too indulgent of the West, upset relations with the Russian Orthodox in 2018 with his decision to establish a new Orthodox body in Ukraine by granting autocephaly to the Ukrainian Orthodox Church.

As a result, the Russian Orthodox formally broke ties, and relations have been strained ever since.

Relations between the Holy See and the Russian Orthodox patriarchate, led by Patriarch Kirill, have traditionally been fraught with tension, and were complicated further with Russia’s invasion of Ukraine in 2022 and the full-blown war that broke out as a result.

Pope Francis and Patriarch Kirill had held a historic first meeting, the first between a pope and a Russian patriarch, in Havana, Cuba, in 2016.

The Vatican pulled the plug on a scheduled second encounter in the summer of 2022 at the last minute due to the diplomatic fallout it would have created given Kirill’s vocal support of the war in Ukraine, which Kirill has repeatedly defended on religious grounds as an opposition to western secularism.

Discussions were in the works to arrange a second meeting, however, the Russian Orthodox in 2023 froze dialogue with the Vatican over doctrinal disputes with Pope Francis’s Fiducia Supplicans.

Speaking to Crux ahead of the liturgy, Swiss Cardinal Kurt Koch said it was the Patriarchate of Constantinople who issued the invitations to Friday’s ecumenical prayer service in Iznik, and the Russian Orthodox was not on the list of invitees.

The decision, he said, was to invite the oldest Orthodox churches, which include the patriarchates of Constantinople, Alexandria, Antioch, and Jerusalem.

“The Catholics have invited Catholics, and the Orthodox invite Orthodox,” he said, saying the decision not to invite the world’s largest Orthodox church “is a decision. I respect the decision of the Orthodox.”

Koch celebrated the fact that Leo XIV is the first pope to ever set foot in what was formerly Nicaea, saying the joint prayer, regardless of tensions that still exist, is a time when the churches can “celebrate together this anniversary and deepen the Christological faith, because this is the fundament of the Christian faith.”

“We can re-find unity only in faith. When we confess the Christological faith of the Council of Nicaea together, I think this is very is an important path for the future,” he said.

He insisted that faced with contemporary challenges, “it is very important that Christians are united, as is the motto of Pope Leo XIV, In illo Uno unum, which means that we are many, we are different, but we are united in Christ.”

“The Church must be united because only in this way, it can be a sign and work for unity in the whole of humanity in a very, very divided and wounded world, by war and conflicts,” he said.

Patriarch Bartholomew in welcoming remarks during Friday’s prayer liturgy thanked Pope Leo for his presence, saying, “Despite so many intervening centuries, and all the upheavals, difficulties, and divisions they have brought, we nevertheless approach this sacred commemoration with shared reverence and a common feeling of hope.”

He noted that Nicaea derives from the Greek word for victory, saying, “When the fallen world thinks of victory, it thinks of force and domination. But as Christians, we are ordered to think differently. Our paradoxical sign of victory is the unconquerable sign of the Cross.”

“This is ‘foolishness’ to the nations, a sign of defeat, but for us, it is a supreme manifestation of the wisdom and power of God. We do indeed celebrate victory in this place, but it is a victory not of this world, and ‘not as the world gives’,” he said.

Pope Leo in his homily said the anniversary of the Council of Nicaea is an opportunity to remember who Christ is for the Christians of modern times.

Christians, he said, often face the risk of reducing Jesus Christ, “to a kind of charismatic leader or superman, a misrepresentation that ultimately leads to sadness and confusion.”

The Arian heresy that denied Jesus’s divinity reduced him to a mere intermediary between the human and divine, which remained separated, the pope said, but challenged that notion, saying, “if God did not become man, how can mortal creatures participate in his immortal life?”

Belief in Jesus’s divinity and the creed that Christians now share is a an invitation to further unity, he said, saying, “although we Christians are many, in the one Christ we are one.”

“We are all invited to overcome the scandal of the divisions that unfortunately still exist and to nurture the desire for unity for which the Lord Jesus prayed and gave his life,” he said.

Pope Leo insisted that the more Christians are reconciled among themselves, “the more we Christians can bear credible witness to the Gospel of Jesus Christ, which is a proclamation of hope for all.”

“Moreover, it is a message of peace and universal fraternity that transcends the boundaries of our communities and nations,” he said.

He closed his homily voicing gratitude to Patriarch Bartholomew I, who had been a good friend of Pope Francis, for taking the initiative in holding a joint commemoration of the 1700th anniversary of the Council of Nicaea in the place where it originally took place.

Leo also thanked the leaders and representatives of other Christian churches present for their participation.

“May God the Father, almighty and merciful, hear the fervent prayers we offer him today, and grant that this important anniversary may bear the abundant fruits of reconciliation, unity and peace,” he said.

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