The Christian doctrine of the Trinity (Trinitas, ‘triad’, trinus “threefold”) holds that God is one God, but three coeternal and consubstantial persons: the Father, the Son (Jesus Christ), and the Holy Spirit. The three persons are distinct, yet are one “substance, essence or nature” (homoousios). In this context, “nature” is what one is, whereas a “person” is who one is.
The subset of Christianity that accepts this doctrine is collectively known as Trinitarianism, while the subset that does not is referred to as Nontrinitarianism (see also Arianism). Trinitarianism contrasts with positions such as Binitarianism (one deity in two persons) and Monarchianism (no plurality of persons within God), of which Modalistic Monarchianism (one deity revealed in three modes) and Unitarianism (one deity in one person) are subsets.
The doctrine of the Trinity was first formulated among the fathers of the Church in the third century as early Christians attempted to rationalize the relationship between Jesus and God in their scriptural documents and prior traditions.
Jesus (c. 4 BC – c. AD 30 / 33), also referred to as Jesus of Nazareth and Jesus Christ or simply Christ, was a first-century Jewish preacher and religious leader. Jesus, The Son of Mary is the central figure of Christianity and also prophet in Islam is widely described as the most influential person in history. Most Christians believe he is the incarnation of God the Son and the awaited Messiah (Christ) prophesied in the Old Testament.