<P> The Ante - Nicene Fathers asserted Christ 's deity and spoke of `` Father , Son and Holy Spirit '' , even though their language is not that of the traditional doctrine as formalised in the fourth century . Trinitarians view these as elements of the codified doctrine . Ignatius of Antioch provides early support for the Trinity around 110 , exhorting obedience to `` Christ , and to the Father , and to the Spirit '' . Justin Martyr ( AD 100 -- c. 165 ) also writes , `` in the name of God , the Father and Lord of the universe , and of our Saviour Jesus Christ , and of the Holy Spirit '' . The first of the early church fathers to be recorded using the word `` Trinity '' was Theophilus of Antioch writing in the late 2nd century . He defines the Trinity as God , His Word ( Logos ) and His Wisdom ( Sophia ) in the context of a discussion of the first three days of creation . The first defence of the doctrine of the Trinity was in the early 3rd century by the early church father Tertullian . He explicitly defined the Trinity as Father , Son , and Holy Spirit and defended the Trinitarian theology against the `` Praxean '' heresy . St. Justin and Clement of Alexandra used the Trinity in their doxologies and St. Basil likewise , in the evening lighting of lamps . </P>
who first held that the trinity is defined as one substance in three persons
Theophilus of Antioch