Milestones for the Next Council: Conciliar Experiences and Global Synodality

In order to deal with the next ecumenical council, this chapter reminds some features of the sixteenth centenary of the Council of Nicaea (325). In 1925, divided churches organized rival celebrations of this deciding event of ancient Christianity. The seventeenth centenary of Nicaea in 2025 could be an opportunity for churches to go further toward the next ecumenical council which raises political, doctrinal, ecological, and technical questions, especially on the ecclesiological level about synodality and changes in the churches.