<P> The corresponding word in Greek is tριάς, meaning "a set of three" or "the number three". The first recorded use of this Greek word in Christian theology was by Theophilus of Antioch in about the year of 170 . He wrote: </P> <P> In like manner also the three days which were before the luminaries, are types of the Trinity (Τριάδος), of God, and His Word, and His wisdom . And the fourth is the type of man, who needs light, that so there may be God, the Word, wisdom, man . </P> <P> Tertullian, a Latin theologian who wrote in the early 3rd century, is credited as being the first to use the Latin words "Trinity", "person" and "substance" to explain that the Father, Son, and Holy Spirit are "tres personae, una substantia". While "personae" is often translated as "persons," the Latin word personae is better understood as referring to roles as opposed to individual centers of consciousness . </P> <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 formalized 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, following the early Christian practice of identifying the Holy Spirit as the Wisdom of God . The first defense 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 his theology against "Praxeas", though he noted that the majority of the believers in his day found issue with his doctrine . St. Justin and Clement of Alexandra used the Trinity in their doxologies and St. Basil likewise, in the evening lighting of lamps . Origen of Alexandria (AD 185 - c. 253) has often been interpreted as Subordinationist, but some modern researchers have argued that Origen might have actually been anti-Subordinationist . </P>

Who came up with the doctrine of the trinity