1.

Augustin, in the first place, contributed much to the development of the doctrinal basis which Catholicism and Protestantism hold in common against such radical heresies of antiquity as Manichaeism, Arianism, and Pelagianism. In all these great intellectual conflicts he was in general the champion of the cause of Christian truth against dangerous errors. Through his influence the canon of Holy Scripture (including, indeed, the Old Testament Apocrypha) was fixed in its present form by the councils of Hippo (393) and Carthage (397). He conquered the Manichaean dualism, hylozoism, and fatalism, and saved the biblical idea of God and of creation, and the biblical doctrine of the nature of sin and its origin in the free will of man. He developed the Nicene dogma of the Trinity, in opposition to tritheism on the one hand, and Sabellianism on the other, but also with the doubtful addition of the Filioque, and in opposition to the Greek, gave it the form in which it has ever since prevailed in the West. In this form the dogma received classical expression from his school in the falsely so called Athanasian Creed, which is not recognized by the Greek Church, and which better deserves the name of the Augustinian Creed.

In Christology, on the contrary, he added nothing new, and he died shortly before the great Christological conflicts opened, which reached their oecumenical settlement at the council of Chalcedon, twenty years after his death. Yet he anticipated Leo in giving currency in the West to the important formula: "Two natures in one person." ¹