Bible & Christianity › Early church & the councils › Council of Nicaea
The Trinity: Father, Son and Holy Spirit
Latin 'trinitas' first used by Tertullian c. 213; defined 325–381· Teaching or doctrine· Church, doctrine & the world
Faith & scriptureHeld by believers on faith and scripture; history can neither confirm nor rule it out.
The Christian belief that one God exists as three persons, Father, Son and Holy Spirit, equal and eternal.
See it on the Bible & Christianity map →What it is
The word 'Trinity' is not in the Bible, but its pieces are: Jesus sends his disciples to baptize 'in the name of the Father and of the Son and of the Holy Spirit' (Matthew 28:19). Tertullian coined the Latin 'trinitas' around 213. Nicaea (325) declared the Son 'of one being' with the Father; Constantinople (381) added that the Spirit is worshipped with them. Three Cappadocian bishops summed it up: one essence, three persons.
Why it matters
It is the dividing line of mainstream Christianity: Catholic, Orthodox and nearly all Protestant churches affirm it; Jehovah's Witnesses, Latter-day Saints and Unitarians do not.
Faith and history
A matter of faith. Historians can trace how the wording was hammered out, through Tertullian, Origen and the councils of 325 and 381, but cannot test the claim itself.
Questions and debates
Catholics and Orthodox still differ over the 'filioque': whether the Spirit proceeds from the Father alone or 'and the Son', a factor in the 1054 split.
Connections (3)
▸Baptism of Jesus in the Jordan is read as an early picture of The Trinity: Father, Son and Holy SpiritFaith & scripture
The connection
At the Jordan, Jesus comes up from the water, the Spirit descends 'like a dove', and a voice from heaven says, 'You are my beloved Son' (Mark 1:10–11). Christians read this as Father, Son and Spirit appearing together. Orthodox churches call the feast (January 6) 'Theophany', the revealing of the Trinity.
When and where
The Jordan River, around AD 28; the Trinitarian reading appears in writers like Tertullian (c. 200) and the 4th-century Cappadocian bishops.
How do we know?
An interpretation, not a historical link. Historians consider the baptism by John very likely; the voice and dove are matters of faith, and the Gospels never say 'Trinity'.
Questions and debates
Whether the Gospel writers meant anything like later doctrine is debated; some early Christians ('adoptionists') read the baptism as the moment Jesus became God's Son.
▸The Nicene Creed confesses The Trinity: Father, Son and Holy SpiritHistorical record
The connection
The 325 creed declared the Son 'of one being' with the Father. The 381 version added a paragraph on the Holy Spirit, 'the Lord, the giver of life, who proceeds from the Father, who with the Father and the Son is worshipped and glorified'. Together they set the standard wording of the Trinity.
When and where
Nicaea (325) and Constantinople (381); the Western addition 'and the Son' (filioque) appeared at Toledo, Spain, in 589 and was adopted at Rome by 1014.
Historical evidence
The creed's texts survive; the 381 wording is first attested in the minutes of Chalcedon (451).
Questions and debates
The filioque still divides Catholics and Orthodox; Catholics sometimes recite the creed without it in ecumenical settings, and some Anglicans have recommended dropping it.
▸Arius and the Arian controversy provoked the defining of The Trinity: Father, Son and Holy SpiritHistorical record
The connection
By denying that the Son was eternal and equal with the Father, Arius forced bishops to define exactly what they believed. That produced the term homoousios (325) and, later, the Cappadocian formula: one essence (ousia), three persons (hypostases). Without the controversy, the doctrine might have stayed far less precise.
When and where
Alexandria from about 318; debated across the empire until 381; resolved by Basil of Caesarea, Gregory of Nazianzus and Gregory of Nyssa.
Historical evidence
Writings from both sides survive, including Athanasius's Orations Against the Arians and Basil's On the Holy Spirit (c. 375).
Questions and debates
Was the Trinity already implied in earlier Christian faith (the traditional view) or worked out through these debates (many historians)? Many say both.