An international dialogue between Catholics and Mennonites took place between 1998 and 2003, beginning with the theme “Toward a Healing of Memories”, and concluding with a report entitled Called Together to be Peacemakers (CTBP). In the hope that, on the basis of that dialogue, Catholics and Mennonites may together offer suggestions for the World Council of Churches’ Decade to Overcome Violence (DOV), and especially in reference to the International Ecumenical Peace Convocation (IEPC) in 2011 with which it culminates, the Pontifical Council for Promoting Christian Unity and the Mennonite World Conference sponsored a brief conference 23–25 October 2007 in consultation with the DOV office. It took place at the Centro Pro Unione in Rome. As a result we now submit some theological reflections which Mennonites and Catholics, committed to overcoming violence, may affirm together as a witness to peace in the ecumenical context. We hope these reflections can be useful to others as preparation continues for the IEPC. We begin by identifying biblical and theological foundations of peace. These appear under the sub-headings of Creation, Christology, and Ecclesiology. Then follows a section on peace and discipleship. We conclude with some challenges and recommendations which might be considered as the focus of workshops at the IEPC.