Peter De Mey (Dendermonde, 1966) is full Professor of Roman-Catholic ecclesiology and ecumenism at the Research Unit of Systematic Theology and the Study of Religions, Faculty of Theology and Religious Studies, KU Leuven. He is involved in the Centre for Ecumenical Research and the Louvain Center for Eastern and Oriental Christianity (LOCEOC). 24 dissertations have successfully been defended under his guidance and many research projects have been obtained. Peter De Mey is the founding chair of the Vatican II Studies group (2012-2016) of the American Academy of Religion. During 2004-2010, he was secretary and then president of Societas Oecumenica, the European Society for Ecumenical Research. He regularly participates in meetings of the Ecclesiological Investigations Network and the Peter