
The Legacies of Nicaea I and Vatican II:
An Inheritance Unfolding
September 4-7, 2025
Marquette University, Milwaukee, Wisconsin
Two councils
Ecumenical (“worldwide”) councils are among the most significant events in the history of Christianity. They constitute the highest legislative and judicial gatherings in the life of the Church, often convened during moments of crisis in which the Christian world recognizes the need to unite as one body and to speak as one voice, seeking to resolve controversy, to define doctrine, to judge canonical or pastoral matters, and to discern the path forward in light of contemporary questions and demands.
The Catholic Church acknowledges twenty-one ecumenical councils, from Nicaea I (325) to Vatican II (1962-5). The year 2025 will mark two important anniversaries: 1700 years since the first ecumenical council, honored as such by all Christians, and 60 years since the closing of the most recent ecumenical council in the Catholic tradition. To commemorate these anniversaries, Catholic institutions in Milwaukee, Wisconsin and beyond are sponsoring an academic conference which will be hosted at Marquette University.

One conference
The fruit of a collaboration between Marquette University, Sacred Heart Seminary and School of Theology, Saint Francis de Sales Seminary, the St. Irenaeus Institute for Catholic Thought, and the Archdiocese of Milwaukee, the Legacies Conference will gather Catholics and other Christians from around the world to celebrate and to study these two councils, their consequential legacies, and the conciliar tradition as a whole. The conference will feature plenary talks from bishops and senior scholars, along with academic papers on a variety of topics related to these themes.
Conference Speakers

Most Rev. Daniel E. Flores

Most Rev. Gregory John Mansour

Lewis Ayres

Robin Darling Young

Susan K. Wood, SCL

Stephen Bullivant

Marcus Plested

Rev. Andrew Summerson

Ellen Scully

Shaun Blanchard

David Luy
General Conference Schedule: 2025
Free transportation will be available between the Ambassador Hotel / Marquette University and the other sites of the conference.
Thursday, September 4, 7:00 PM
Brookfield Conference Center- Opening Pallium Lecture by Bishop Daniel E. Flores, preceded by a cocktail reception
Friday, September 5, all day
Marquette University- Concurrent sessions with papers on Nicaea I and its legacy
- Two keynote lectures by Lewis Ayres and Robin Darling Young
- Evening plenary address by Bishop Gregory John Mansour
Saturday, September 6, all day
Marquette University- Concurrent sessions with papers on Vatican II and its legacy
- Two keynote lectures by Susan K. Wood and Stephen Bullivant
- Evening plenary discussion and Q&A with featured speakers followed by a dessert reception
Sunday, September 7, 9:00 AM
Cathedral of St. John the Evangelist- Closing Mass with the Archbishop of Milwaukee
Submit a paper proposal
Paper proposals may be submitted using the portal. Please note that papers related to Nicaea will be scheduled on Friday and papers related to Vatican II will be scheduled on Saturday. The deadline to submit a proposal is March 1, 2025.
Paper topics may include, but are not limited to, the following:
- The Council of Nicaea and its reception history
- The Nicene Creed and other Christian confessions
- Trinitarian theology and Christology in view of Nicaea
- Athanasius, Arius, and "Arianism"
- Orthodoxy and heresy in Christian tradition
- Unity and schism in Church history
- Constantine and Christianity in the Roman Empire
- Ecumenical councils and the conciliar tradition
- The Second Vatican Council and its reception history
- The proceedings and documents of Vatican II
- Liturgy and liturgical developments before or after Vatican II
- Synods and synodality
- The Church in the modern world
- Ecumenism and ecumenical relations between the Catholic Church and other ecclesial bodies
*Selected papers will be included in an edited volume of the conference proceedings.

Dining and accommodation
Lunch passes for use at Marquette’s dining halls can be purchased during registration. Breakfast snacks and coffee are included in the price of registration.
Hotel rooms can be booked here through the Ambassador Hotel at a discounted rate for those participating in the Legacies Conference. The hotel is located only one (1) mile from Marquette University and includes a free shuttle service to and from the university.
A special thanks to our local and regional sponsors who made this event possible.











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