About

The Ecclesiological Investigations International Research Network (EIIRN) will hold an international conference on September 17-19, 2025, in Thessaloniki, Greece, in recognition of the 1700th anniversary of the First Council of Nicaea. Our collaborators include the Center for Ecumenical, Missiological, and Environmental Studies (CEMES), the American College of Thessaloniki, Graymoor Ecumenical & Interreligious Institute, Boston College, Princeton Theological Seminary, and other partners. For the full list of conference sponsors see here. The purpose of the conference is to pose the questions:  In what ways does Nicaea continue to shape how we configure the Church today, with what opportunities and at what cost?  The conference will eschew foregone conclusions and panegyrics, instead being intended as an intensely interdisciplinary and ecumenical laboratory for exploring the ways that Nicaea can serve as a lens for interpreting the ecclesial present and imagining the ecclesial future.

The First Council of Nicaea, convened in 325 AD by the Emperor Constantine I, inaugurated an enduring paradigm not only in ecclesial administration (by consolidating its conciliar and synodal processes) but also in church identity. The Council’s processes and conclusions remain broadly normative with regard to church polity and the limits of Christian diversity. Council Fathers committed themselves to shared language (such as the Creed) without overdetermining a shared interpretation; they likewise established prevailing norms in the relationship between ecclesial authority and political and cultural power in what was then the Roman Empire. Given that Nicaea took place at a time of remarkable religious pluralism and diversity and was convened in response to the disputes over “what is the Church” within that context, that early ecclesial reality shares an important resonance with our current historical moment. The problems that the Council resolved, the disputes that it left unresolved, and the new problems and controversies that emerged as a result of the Council’s deliberations therefore offer lenses through which the analogous challenges and emerging debates that face the churches in the twenty-first century may be viewed. 

English will be the working language for all sessions of the conference. The majority of the conference sessions will be held at the American College of Thessaloniki, our host institution in Thessaloniki and one of the conference co-sponsors.