Dietmar W. Winkler is Professor of Patristic Studies and History of Christianity, chair of the Department of Biblical Studies and Ecclesiastical History and Director of the Center for the Study of Eastern Christianity at the University of Salzburg/Austria, Member of the board of Pro Oriente (Vienna) and responsible theologian for the dialogue with the oriental churches, Scholarly director of “Pro Oriente Studies in the Syriac Tradition”. Consultant of the Pontifical Council for Promoting Christian Unity (Vatican) and a member of the Vatican’s Delegation in the official “International Joint Commission for Theological Dialogue between the Catholic Church and the Oriental Orthodox Churches”