Père Henri de Riedmatten, O.P., le Keywords: Catholicism | Development of international law | Mots clefs: Catholicisme | Développement du droit international | ABSTRACT Henri de Riedmatten’s course focuses on the legal impact of the teaching about international life by the Magisterium in the Catholic Church (supreme doctrinal authority of the church, Pope and Ecumenical Council), during the pontificates of John XXIII and Paul VI. The author successively presents a teaching commanded by the search for peace, two sources…