a.  The Five Theological Orations.—These won him the title of The Theologian.  They were delivered in Constantinople, in defence of the Church’s faith in the Trinity, against Eunomians and Macedonians.  In the First and Second he treats of the existence, nature, being, and attributes of God, so far as man’s finite intellect can comprehend them.  In the Third and Fourth the subject is the Godhead of the Son, which he establishes by exposition of Scripture, and by refutation of the specious arguments brought forward by the heretics.  In the Fifth he similarly maintains the Deity, and Personality of the Holy Ghost.