5. Tertullian. Tertullian (about 220) can not escape the charge of subordinationism. He bluntly calls the Father the whole divine substance, and the Son a part of it, illustrating their relation by the figures of the fountain and the stream, the sun and the beam. He would not have two suns, he says; but he might call Christ God, as Paul does in Rom. ix. 5 . The sunbeam, too, in itself considered, may be called sun, but not the sun a beam. Sun and beam are two distinct things (species) in one essence (substantia), as God and the World, as the Father and the Son. But figurative language must not be taken too strictly, and it must be remembered that Tertullian was especially interested to distinguish the Son from the Father, in opposition to the Patripasaian Praxeas. In other respects he did the Church christology material service. He propounds a threefold hypostatical existence of the Son (filiatio): (1) The preexistent, eternal immanence of the Son in the Father, they being as in separable as reason and word in man, who was created in the image of God, and hence in a measure reflects his being; (2) the coming forth of the Son with the Father for the purpose of the creation; (3) the manifestation of the Son in the world by the incarnation. He advocates the entire yet sinless humanity of Christ, against both the Docetistic Gnostics (Adv. Marcionem and De carne Christi ) and the Patripaesiana (Adv. Praxeam ). He accuses the former of making Christ, who is all truth, a half lie, and, by the denial of his flesh, resolving all his work in the flesh into an empty show. He urges against the latter that God the Father is incapable of suffering and change. Professor Warfield (see bibliography) lays much stress upon the definition which Tertullian gives of the Trinity, and regards Tertullian rather than Origen as the real father of the Christian doctrine of the Trinity.

6. Dionysius of Rome. Dionysius, bishop of Rome (262), came nearest the Nicene view. He maintained distinctly, in the controversy with Dionysius of Alexandria, the unity of essence and the threefold personal distinction of Father, Son, and Spirit, in opposition to Sabellianiam, tritheiam, and subordinationiam. His view is embodied in a fragment preserved by Athanasius (De sententiis Dionysii, iv., and Routh, Reliquiae sacrae, iii., Oxford, 1846, p. 384).