Ecumenical Councils

The dogma of the Trinity was defined, by ‘trial and error’ over the course of theological rows, within the framework of the Ecumenical Councils of the first five centuries of our common era. This dogma had been proclaimed, for the first time, at the end of the first Ecumenical Council in the history of the Church, convened at the initiative of the Emperor Constantine, in 325 in Nicaea – which remains known by the name of the First Council of Nicaea – to rebut the teaching of Arius, an Egyptian priest of Alexandria whose doctrine, expressed in the 3rd century, taught that Jesus Christ was the first begotten of God the Father’s creatures, superior to all the other created beings because of this, and different in nature and, consequently, inferior to the Father, who alone is transcendent, uncreated, unbegotten and eternal. Arianism was considered heretic by the Bishops present, who ‘solemnly proclaimed the full divinity of the Son, begotten, not made, consubstantial with the Father’, nonetheless without offering any precision as regards the Spirit, the third Person of the Trinity. The latter would only enter the Symbol of faith or credo in 381, proclaimed at the closing of the First Council of Constantinople, which completed the previous one: thus was cast in textual form the Christian belief in a single God in three equal and distinct persons, forming one and the same substance. Eastern in origin, Arianism spread through the West, notably amongst the Barbarian kings.

Called together in 431, the Council of Ephesus denounced the doctrine of Nestorius, Patriarch of Constantinople from 428 to 431, who tended to understand the two natures of Christ – divine and human – as two persons and disagreed with the expression ‘Mother of God’ to designate the Virgin Mary. The views of Cyril, Patriarch of Alexandria, prevailed, arguing for the union of the human and the divine in Christ in one single nature.

The site of a theological clash between one strand of thought affirming that ‘unique is the nature of the divine Word which is incarnated’ and another insisting on the co-existence of two natures forming ‘a sublime, ineffable, indissoluble conjunction,’ the question of the Trinity was once again tackled at the Council of Chalcedon in 451. The Bishops who met together there, rejecting the monophysism championed by a Constantinople monk by the name of Eutyches, who stated that there was just one nature in Christ (divine nature being so superior to human nature that it tended to absorb it), thus came to an agreement over the definition of the person of Christ as the union of two natures, ‘without confusion, without change, without division, without separation,’ preserving their respective properties without undermining the Hypostatic Union: ‘the orthodox faith was to believe that the divine person of the Word had remained in the Flesh which it was for all eternity: the eternal Son of God’; ‘the only Son of God and Mary’s first born were one and the same person.’ And the final text, which thus allowed the Church to agree on an official definition of the person of Jesus, added that: ‘All this having been fixed and formulated by us with all possible precisions and care, the Holy and Ecumenical Council has decided that nobody is permitted to profess or write a new expression of faith, or to teach others.’