Homoiousios (Greek: ὁμοιούσιος from ὅμοιος, hómoios, "similar" and οὐσία, ousía, "essence, being") is a Christian theological term, coined in the 4th century by a distinctive group of Christian theologians who held the belief that God the Son was of a similar, but not identical, essence (or substance) with God the Father. Homoiousianism arose as an attempt to reconcile two opposite teachings, homoousianism and homoianism. Following Trinitarian doctrines of the First Council of Nicaea (325), homoousians believed that God the Son was of the same (ὁμός, homós, "same") essence with God the Father. On the other hand, homoians refused to use the term οὐσία (ousía, "essence"), believing that God the Father is "incomparable" and therefore the Son of God can not be described in any sense as "equal"