"However, this is no proof in itself that Tertullian taught the Trinity." Should You Believe in the Trinity? p.5

> "As Tertullian erroneously sought to prove the divinity of Jesus by means of another theory, he coined the formula "one substance in three persons." Using this concept, he attempted to show that God, his Son, and the holy spirit were three distinct persons existing in one divine substance. Tertullian thus became the first to apply the Latin form of the word "trinity" to the Father, the Son, and the holy spirit." Watchtower 2002 May 15 p.31