Pope visits Türkiye to mark First Council of Nicaea’s 1,700th anniversary. Why is it so important?

By Yusuf Kamadan

When Pope Leo XIV arrives in Türkiye on November 27 to commemorate the 1700th anniversary of the First Council of Nicaea, he will not merely be retracing an ancient route of Christian history.

His visit stands at the intersection of theology, memory, diplomacy, and identity—an acknowledgement that the foundations of Christianity as we know it today were laid not in the West, but in the towns, valleys, and cities of Anatolia. 

The Pope’s journey, which includes meetings with Turkish leaders in Ankara and a major liturgical ceremony in Iznik (Nicaea), is already being hailed as one of the most symbolic papal trips in decades.

To understand why, one must return to the geography itself. Few regions carry as much weight in early Christian history as Anatolia, a point emphatically underlined by Professor Zafer Duygu of Izmir-based Dokuz Eylul University. 

“Christianity’s development in antiquity and late antiquity has a central geography,” he says. “The title Christian was used for the first time in Anatolia. According to the Acts of the Apostles, the term—derived from Christos, meaning Messiah—was first applied in Antioch in the late first century.” 

This means the very name of the faith, long before it travelled across continents, was crystallised on the soil of what is now Türkiye.

The Anatolian blessing 

Duygu stresses that the earliest Christian communities and churches emerged across this landscape. 

“When you look at Paul’s missionary journeys,” he says, “Anatolia holds a central role.” In the Book of Revelation, the seven churches—Ephesus, Smyrna, Pergamon, Thyatira, Sardis, Philadelphia, and Laodicea—are all located in western Anatolia. “These were considered the most significant communities of antiquity.”  

The region also produced some of the Church’s most influential early martyrs and theologians. “Ignatius of Antioch, Polycarp of Smyrna—these are the earliest martyrs and key figures in shaping Christian theology.”

Across Cappadocia, Phrygia, Bithynia, and the Aegean coast, Christian thought bloomed. The Cappadocian Fathers—Basil the Great, Gregory of Nazianzus, and Gregory of Nyssa—laid the intellectual foundations of the doctrine of the Trinity. 

Entire movements arose here, both orthodox and other sects that were pushed out by mainstream Christianty, from Marcion in Sinope to Montanus in Phrygia. 

“There are so many clergy we could list,” Duygu says, “we could give more and more examples. Saints, martyrs, theologians—the overwhelming majority emerged from Anatolia.”

This is not a regional exaggeration. The first great councils of the Christian world—gatherings that still bind nearly all major Christian traditions today—were held in Anatolia. 

Between 325 and 553, Nicaea, Constantinople, Ephesus, Chalcedon and other regions hosted the deliberations that shaped global Christian orthodoxy. 

“These councils remain binding for every Christian community that claims the title today,” says Duygu. 

The Nicea legacy 

“The 325 Council of Nicaea is one of the most decisive moments, and it took place right here, in present-day Iznik”, he says. 

The significance of the Council of Nicaea is difficult to overstate. Convened by Emperor Constantine—“who was integrating the Church into the state system,” the council produced the Nicene Creed, the foundational declaration of Christian belief. 

According to the creed, Jesus Christ was not a created being but “of the same essence” (homoousios) with God the Father. 

“It was at Nicaea that the belief that Christ is fully divine and eternal was affirmed,” he says. Arius and his followers, who held alternative views of Christ’s nature, were excommunicated.

Yet the Council’s significance was not solely theological. It also structured the administrative hierarchy of the Church. Rome, Antioch, and Alexandria were designated as the major centres, each given a patriarch. This would later lead to centuries of rivalry, schisms, and competing claims of authority—but the framework was laid in Iznik. 

“The emperor created an ecclesiastical hierarchy,” Duygu says. “Its purpose was political: to extend central authority through the Church.”

In light of this, Pope Leo XIV’s visit carries deep symbolic resonance. The Pope is both a spiritual leader and a head of state. His itinerary reflects both roles: diplomatic meetings in Ankara, and then a pilgrimage to Iznik for a joint ceremony with Patriarch Bartholomew, the Greek Orthodox Patriarch of Fener, accompanied by anticipated declarations.

The eternal bond 

Peder Severin, priest of the Mary Mother of the Rosary Church in Istanbul’s Bakirkoy district, underscores the emotional and spiritual meaning of the visit. “Türkiye is extremely important for Christianity in terms of history. The first 300 years of the Church passed on these lands.” 

For Christians living in Türkiye today, the Pope’s visit is both a reminder of ancient roots and a sign of inclusion. “We are part of this country,” he emphasises. “We want to contribute to its future.”

As preparations intensify and Iznik anticipates an influx of pilgrims, clergy, scholars, and journalists, the world’s attention turns again to the quiet lakeside town where a doctrinal revolution once unfolded. 

“This is Pope Leo’s first trip abroad. It will go down in history.”