A forgotten centenary: The Council of 879-880 - Part 1

This article constitutes the first part of a historical study devoted to the Council of Constantinople of 879-880, held under the patriarchate of Photius and remaining largely unknown despite its importance. Adopting a rigorous ecclesiastical history approach, the author traces the antecedents of the council — the conflict between Photius and Pope Nicholas I, the role of the Bulgarian question, the Ignatian council of 869-870 — before setting out its proceedings session by session. The main contribution of the article is to show that this council constituted the only truly successful council of union between Rome and Constantinople: it rehabilitated Photius, established a principle of reciprocity between the two sees, and prohibited any addition to the creed, implicitly targeting the Filioque. The author also refutes the legend of a "second Photian schism" and highlights the ecumenical dimension, too long neglected, of the patriarch's actions.