The Council of Constantinople of 879-880 — III. The question of the "Filioque"

This article constitutes the third installment of a historical and theological study devoted to the Council of Constantinople of 879-880. It examines the way in which this council addressed the question of the *Filioque*, through the analysis of the decree of the sixth session prohibiting any modification of the Nicene-Constantinopolitan Creed, the critical study of a letter attributed to Pope John VIII to Photius, and the examination of Photius's later writings on the procession of the Holy Spirit. The article shows that the consensus reached in 879-880 rested on a fundamental ambiguity between the Greek and Latin positions, without the doctrinal question being resolved. Its principal contribution is to demonstrate that the *Filioque* was not, at that time, a cause of rupture between Rome and Constantinople, and to propose a return to the original text of the Creed as an ecumenical path that remains relevant today.