This paper illustrates the progression of the Christian faith from a persecuted, underground movement to the center of Roman public life. Constantine’s choice of Nicaea for the first ecumenical council was not only a strategic choice but also a symbolic statement for repositioning the place of Christianity in civil affairs. The First Council of Nicaea met in the recently discovered underwater basilica in Iznik (Nicaea). That basilica began as a martyrion for a saint that had been executed years earlier outside the walls of Nicaea on the shore of Lake Ascania. In the years thereafter, the tomb of the saint became a place of worship for the Christians of Nicaea. Other Christians were buried near the martyr’s tomb and a wall was constructed around the site, creating a Christian shrine. Following the Edict of Milan (313), the shrine was enlarged as a church. It was there, outside the walls of Nicaea, that the first known church was constructed. At the conclusion of the council, Constantine gathered the bishops into his palace inside the city for the final vote on the issues and the formation of the Nicaean Creed.
The council became a turning point in the history of Christianity. From a clandestine religion operating discreetly within society, within a few short years the Chrisian faith emerged with imperial sanction. In the centuries that followed at least fourteen Byzantine sanctuaries and basilicas were constructed within the walls of Nicaea. The seventh and final ecumenical council met in 787 in Nicaea at the Hagia Sophia, located in the Roman forum of the city, at the juncture of the Cardo Maximum and the Decumanus Maximus.
The first basilica at Nicaea is now submerged beneath Lake Iznik (ancient Ascania). During the recent excavations, a pilgrim token was discovered among the remains, indicating that the site was a place of pilgrimage. Centuries following the submersion of the basilica, the Hagia Sophia became the centerpiece and symbol of Nicaea. The symbolism of this movement is important: from outside the city to the center of civic life, from a persecuted faith to a faith with imperial approbation. This year we celebrate the 1700th anniversary of the First Council of Nicaea.
Cf. Mark R. Fairchild, The Underwater Basilica of Nicaea: Archaeology in the Birthplace of Christian Theology, IVP Academic, 2024.