Archaeologists in Turkey believe they've made a groundbreaking discovery, possibly uncovering the remains of a church they believe hosted the First Council of Nicaea, one of the most pivotal events in the history of Christianity.
An international team of researchers in July excavated a church complex in the ancient city of Nicaea, now within the modern town of İznik, according to Turkish state media outlet Anadolu Agency (AA).
The building, which excavation director Mustafa Şahin identified as the Church of St. Neophytos, was destroyed by an earthquake in 368 A.D.
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It was soon replaced by the Church of the Holy Fathers, built around 380 A.D.
Pictures show archaeologists excavating the stone foundations of the ancient church complex along the shore of Lake İznik, where trenches have exposed centuries-old walls and masonry.
Şahin told AA his team was tipped off to the existence of a smaller church after discovering that the floor paving extended beyond the walls of the existing basilica.
"That was our most important question this season," he said. "We began excavating east of the prothesis, outside the church's exterior wall."
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He added, "At the end of the first week, as we had hoped, we discovered that the floor paving continued beyond the existing church."
Nicaea is famous for hosting the First Council of Nicaea in 325 A.D. — the first-ever ecumenical council in Christian history.
BURSA, TURKIYE â" JULY 08: An aerial view of the archaeological excavation site where the remains of walls, floor paving and a column base belonging to the church that hosted the First Council were uncovered in Iznik district of Bursa, Turkiye, on Ju …
The council famously produced the Nicene Creed, affirming that Jesus was "begotten, not made" and fully divine rather than a created being.
It represented one of the earliest efforts to unify Christian doctrine across the Roman Empire, and rejected the beliefs of Arius, who argued that Christ was a created being rather than co-eternal with God the Father.
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Archaeologists first identified a large submerged basilica at the site in 2014, later determining it was the Church of the Holy Fathers.
While that basilica has long been associated with the First Council of Nicaea, Şahin said the newly uncovered, smaller church beneath it is a more likely candidate.
Şahin said coins recovered from graves beneath the later basilica helped date its construction to around A.D. 380, reinforcing his conclusion that an earlier church occupied the site at the time of the council.
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Eusebius of Caesarea, who attended the First Council of Nicaea, described the meeting as taking place in a small church — a detail that Şahin said supports his hypothesis.
"The church was so small that one wonders how so many bishops fit inside," said Şahin. "This itself was a great miracle of God."
After uncovering evidence that the basilica had been built over an earlier church, Şahin said he was confident the Church of Saint Neophytos stood beneath the Church of the Holy Fathers and was the church that hosted the First Council of Nicaea.
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"The Church of the Holy Fathers... was built after 380 over the site of the First Council and in memory of the bishops who attended it," he said.
"As of this year, we are in a position to say definitively that the Church of the Holy Fathers is located here. We are very pleased because our hypothesis has been confirmed."
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Fox News Digital reached out to Şahin.
Turkey has been the site of numerous archaeological discoveries tied to early Christianity.
Last summer, archaeologists excavating the ancient city of Olympos in southern Turkey uncovered a fifth-century Christian church featuring a long-hidden inscription.
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Later that year, archaeologists in southwestern Turkey uncovered the remains of a Roman hospital that was later converted into a Christian sanctuary.
Andrea Margolis is a lifestyle reporter for Fox News Digital and Fox Business. Readers can follow her on X at @andreamargs or send story tips to andrea.margolis@fox.com.