Archaeologists working in the northwestern province of Bursa’s İznik district have uncovered structural remains believed to belong to the Church of St. Neophytos, the modest church that hosted the First Council of Nicaea in A.D. 325, providing the strongest archaeological evidence to date for the long-debated location of one of Christianity’s most important gatherings.
The latest discoveries include wall remains, floor paving and a column base found beneath the ruins of the later lakeside basilica, which was named one of the world’s 10 most significant archaeological discoveries in 2014 by the Archaeological Institute of America.
Excavations have continued since 2015 at the site believed to have hosted Christianity’s first ecumenical council, which established key doctrines shaping the faith. The project operates under permission from the Culture and Tourism Ministry, with support from the Bursa Municipality.
The research is led by Professor Mustafa Şahin, head of the Archaeology Department at Bursa Uludağ University’s Faculty of Arts and Sciences, together with a multidisciplinary team of archaeologists, anthropologists, conservators and art historians. This year’s excavation has also become an international collaboration with researchers from Italy’s University of Calabria and Magna Graecia University of Catanzaro joining the project.
Speaking to state-run Anadolu Agency, Şahin said the team’s primary objective at the start of this excavation season was to determine whether the floor discovered in previous years extended beyond the walls of the existing church.
Earlier excavations had revealed what researchers believed to be paving inside the church’s prothesis chamber, where sacred objects were traditionally kept, but it was unclear whether the floor belonged solely to the later structure or to an earlier building beneath it.
To answer that question, archaeologists opened a new excavation trench east of the chamber. Within the first week of work, they confirmed that the paving continued outside the existing church walls.
According to Şahin, the discovery demonstrates that the present church was constructed over an earlier building, strongly supporting the theory that the Church of St. Neophytos lies directly beneath the later Holy Fathers Church.
“The structure whose foundations and floor we uncovered this year can now confidently be identified as the Church of St. Neophytos, the small church described by Eusebius,” Şahin said.
“We are extremely happy because we have finally found evidence confirming our hypothesis. Understanding within the first week that the earlier church extended beneath the later building represents a major archaeological discovery.”
He explained that the Church of St. Neophytos was destroyed in the earthquake of 368 and that a new church, known as the Holy Fathers Church, was erected on the same site after 380 to commemorate the bishops who attended the First Council of Nicaea and preserve the location where it was held.
The findings also correspond with descriptions by Eusebius of Caesarea, a bishop who participated in the council and later wrote in his work “Vita Constantini” that the gathering took place in a small church so modest in size that it seemed miraculous it could accommodate so many bishops.
Beyond the architectural discoveries, archaeologists unearthed a gold ring decorated with a palm tree and a sword, along with a thimble that resembles examples from the Umayyad and Abbasid periods.
Şahin said the artifacts could help explain the site’s history after the Byzantine period. Historical sources record that Umayyad forces besieged İznik in 729 in an unsuccessful attempt to capture the strategically important city before advancing toward Constantinople. Although the city resisted, historical accounts suggest that an Umayyad commander entered the Holy Fathers Church during the siege.
“The preliminary assessment of the ring and thimble suggests that the Umayyads visited the church we are excavating. These finds are extremely important because the pieces of the puzzle are gradually falling into place,” Şahin said.
Meanwhile, Italian researchers are continuing excavations in the basilica’s central nave, where previous seasons uncovered eight burials, including two directly beneath the bema wall, the elevated area reserved for senior clergy.
Mortar traces on the skeletons indicated the graves predated the construction of the church, while coins recovered from two of the burials date to the reigns of the Roman emperors Valens and Valentinian. Those discoveries previously enabled archaeologists to date the construction of the Holy Fathers Church to around A.D. 380.
Şahin said the team hopes this year’s investigations in the central nave will provide further evidence about the basilica’s earliest phases and the transformation of one of Christianity’s most sacred sites over the centuries.
The discoveries come less than a year after Pope Leo XIV visited İznik on Nov. 28, 2025, to attend ceremonies marking the 1,700th anniversary of the First Council of Nicaea, highlighting the site’s enduring significance for the Christian world.
