Lost Church of the First Council of Nicaea Emerges Beneath Iznik Basilica

Researchers excavating at the ancient city of Nicaea, located in modern day İznik, in the northwestern part of Turkey, have come across compelling evidence that they have discovered the original church location where the First Council of Nicaea met in the year 325 AD. The First Council of Nicaea was one of the most important events in early Christianity. The discoveries at the site include the foundations of the wall, floor structures, and architectural features. In the view of the researchers, these features strongly suggest that the remains belong to the Church of Saint Neophytos, a structure long debated by scholars.

The excavation is part of the eleventh archaeological season at the lakeside basilica site and has been led by Professor Mustafa Şahin of Bursa Uludağ University. According to the excavation team, the main objective of the 2026 season was to locate the small church mentioned in historical sources as the site of the First Council. The researchers discovered a distinctive floor surface that extended beyond the footprint of the later basilica. This proves that a larger church was built over an earlier, smaller sanctuary.

Excavation team members examine wall and floor remains uncovered at the İznik basilica site. (AA / Anatolian Archaeology)

An Earlier Sanctuary Revealed

The newly uncovered paving was found outside the eastern wall of the prothesis, a room used for preparing liturgical objects. This difference between the earlier floor plan and the existing structure confirmed the presence of another church that occupied the site before the present basilica was built. Şahin identified this first phase as the Church of Saint Neophytos, which was reportedly destroyed by a massive earthquake in 368 AD.

A second building, known as the Church of the Holy Fathers, was constructed on the site after 380 AD. It was built to honor the bishops who attended the First Council of Nicaea and stood directly over the place where the council had met. The discoveries align perfectly with the accounts of the fourth-century historian Eusebius of Caesarea, who wrote in his Vita Constantini that the council met in a relatively modest church rather than a monumental basilica.

Artifacts Point to Umayyad Presence

In addition to the architectural features, excavations yielded smaller, yet significant, finds. Archaeologists discovered a gold ring decorated with palm tree and sword motifs, along with a bronze thimble. These artifacts bear stylistic similarities to objects from the Umayyad and Abbasid periods.

These finds may support historical accounts that Umayyad forces, who besieged Nicaea in 729 AD, visited the Church of the Holy Fathers. Because the church stood outside the defensive walls of Nicaea, it could have been reached by the besieging army even though the city itself did not fall. Şahin noted that while these objects do not definitively prove they belonged to soldiers involved in the siege, they represent intriguing archaeological traces of an Umayyad presence at the site.

The Legacy of the First Council

The First Council of Nicaea was convened by Emperor Constantine I to bring together bishops from across the Roman Empire to resolve theological disputes within the early Church. The council adopted the original form of the Nicene Creed, a foundational document that profoundly influenced Christian theology.

The location of this historic meeting has long been a central question for researchers at the lakeside basilica. The earlier pavement, walls, and column base now provide the clearest architectural evidence yet for a religious building beneath the later church. As excavations continue in the central nave of the basilica, archaeologists hope to further clarify the building’s architectural order and uncover more secrets about this pivotal site in Christian history.

Top image: Fresco painting of the First Council of Nicaea (Concilium Nicaenum I), Sistine Chapel, Vatican.  Source: Public Domain