Historical Context

Origins

Council of Nicaea (325 AD): Formulated to defend the apostolic faith against the Arian heresy, which claimed the Son was a created being and that there was 'a time when he was not.' The Council affirmed the Son is 'homoousios' (of one substance) with the Father.

Council of Constantinople (381 AD): Expanded the confession regarding the Holy Spirit to refute the 'Pneumatomachi' (fighters against the Spirit) and finalized the text generally used today.

Council of Chalcedon (451 AD): Further clarified the union of the two natures in Christ, rejecting Eutychianism (confusion of natures) and Nestorianism (separation of persons).

Terminology Debates

Ousia vs. Hypostasis: Early debates struggled with terminology. The Fathers eventually distinguished 'ousia' (essence/substance, which is common to the three) from 'hypostasis' (person/subsistence, which is particular to each). St. Jerome expressed hesitation to speak of 'three hypostases' fearing it implied three gods/essences, preferring 'one substance and three persons'.

Rule of Faith: The Creed functions as the 'regula fidei' (rule of faith), a summary of the broad scope of Scripture used to combat heresy. It is not an addition to Scripture but a synopsis of its doctrinal content.