Archaeologists unearth secret church tied to Council of Nicaea, Christianity's defining moment

An international team of researchers continued excavations in July at 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 structure, which excavation director Mustafa Şahin identified as the Church of St. Neophytos, was destroyed by an earthquake in 368 A.D., according to AA.

The latest findings from the excavations align with accounts found in ancient written sources, Şahin told Fox News Digital.

He said researchers discovered that floor pavement outside the later church continued into the prothesis chamber, an area beside the sanctuary, and ran beneath its eastern wall, suggesting it belonged to an earlier phase of the church complex.

"This first phase may correspond to the small church recounted in the written sources [about the Council of Nicaea]," he said.

Speaking to AA, Şahin described how researchers pursued the clue during this season's excavation.

"That was our most important question this season," he said. "We began excavating east of the prothesis, outside the church's exterior wall."

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.

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 told AA the newly uncovered, smaller church beneath it is a more likely candidate.

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, per AA. "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 St. Neophytos stood beneath the Church of the Holy Fathers and was the church that hosted the First Council of Nicaea.

"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 told AA. "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."