At the Council of Nicaea in 325, historical and theological circumstances intertwined to affirm Christ as God through the participation of a large number of bishops and collegial voting.

Defining Christ's Divinity: The Legacy of Nicaea

At the Council of Nicaea in 325, historical and theological circumstances intertwined to affirm Christ as God through the participation of a large number of bishops and collegial voting.

Historically, the council was convened under the auspices of Emperor Constantine the Great, who sought to strengthen the unity of the Church and, consequently, the unity of the entire empire. This decision was driven by the growing threat of division and political instability, exacerbated by disagreements over Arianism. Arius, an Alexandrian priest, denied the divinity of the Son and claimed that Christ was only the highest of creations, contradicting the necessary uniformity of doctrine. As one source explains, "This Council was convened against the heresy of the Alexandrian priest Arius... The Council condemned and rejected Arius’s heresy and affirmed the unalterable truth – the dogma; the Son of God is true God..." (source: link txt).

From a theological perspective, the central issue became defining the nature of Christ: Could faith be complete if the Son were not, by his very essence, truly God?

The bishops gathered there clearly sensed the need to formulate a confession of faith that would affirm Christ as being begotten of the Father "before all ages" and of the same substance with Him. This was necessary not only for internal theological unity but also for the possibility of reuniting believers with God through Christ. One source notes in support of this idea that "The Council’s response was that only if Christ is truly God can He reunite us with God, for only God is capable of opening the way to union. Christ is 'of the same substance' (homoousios) with the Father..." (source: link txt).

Thus, the historical necessity of preserving the Church's unity, supported by the Emperor's backing and the drive to overcome divisions, merged with theological reasoning that required a clear affirmation of Christ's divine nature. As a result of the collective vote, in which 318 bishops participated, the doctrine was established that the Son of God is true God, begotten and not created, and of the same substance as the Father. This doctrinal step was decisive in shaping the Christian understanding of the Divine Trinity and had a long-lasting impact on the development of church dogma.

Supporting citation(s):
" This Council was convened against the heresy of the Alexandrian priest Arius, who denied divinity and the eternal generation of the second Person of the Holy Trinity, the Son of God... The Council condemned and rejected Arius’s heresy and affirmed the unalterable truth – the dogma; the Son of God is true God..." (source: link txt)

" The main business of the Council of Nicaea in 325 was the condemnation of Arianism... The Council’s response was that only if Christ is truly God can He reunite us with God, for only God is capable of opening the way to union. Christ is 'of the same substance' (homoousios) with the Father." (source: link txt)

" At the First Ecumenical Council in Nicaea (325), a confession of faith was adopted in which the relationship between the Son and the Father was defined as consubstantial." (source: link txt)