The Nicaean Creed is the official doctrine of the Roman Catholic Church, Eastern Orthodox Church, Oriental Orthodox, Anglican Church, and most mainline protestant churches with regard to the ontological status of the three persons of the Trinity: Father, Son and Holy Spirit.
Some theologians preferred the use of the term homoiousios (Greek for "of like substance") in order to emphasize distinctions among the three persons in the Godhead, but the term homoousios became a consistent mark of Nicene orthodoxy in both East and West. According to this doctrine, Jesus Christ is the physical manifestation of Logos (or the divine word) and consequently possesses all of the inherent, ineffable perfections which religion and philosophy attribute to the Supreme Being. Three distinct and infinite minds, three co-equal and eternal realities, compose a single Divine Essence (ousia).
This doctrine was formulated in the 4th century CE during the extraordinary Trinitarian or Arian controversy. The several distinct branches of Arianism which sometimes conflicted with each other as well as with the pro-Nicene homoousian creed can be roughly broken down into the following classification:
All of these positions and the almost innumerable variations on them which developed in the 4th century AD were strongly and tenaciously opposed by Athanasius and other pro-Nicenes who insisted on the doctrine of the homoousian (or as it is called in modern terms consubstantiality), eventually prevailing in the struggle to define the dogma of the Orthodox Church for the next two millennia when its use was confirmed by the First Council of Constantinople in 381 or 383.