. The formation of the Tetramorph, or Fourfold Gospel Irenæus, in his work "Against Heresies" (A.D. 182-88), testifies to the existence of a Tetramorph, or Quadriform Gospel, given by the Word and unified by one Spirit; to repudiate this Gospel or any part of it, as did the Alogi and Marcionites, was to sin against revelation and the Spirit of God. The saintly Doctor of Lyons explicitly states the names of the four Elements of this Gospel, and repeatedly cites all the Evangelists in a manner parallel to his citations from the Old Testament. From the testimony of St. Irenæus alone there can be no reasonable doubt that the Canon of the Gospel was inalterably fixed in the Catholic Church by the last quarter of the second century. Proofs might be multiplied that our canonical Gospels were then universally recognized in the Church, to the exclusion of any pretended Evangels. The magisterial statement of Irenæus may be corroborated by the very ancient catalogue known as the Muratorian Canon, and St. Hippolytus, representing Roman tradition; by Tertullian in Africa, by Clement in Alexandria; the works of the Gnostic Valentinus, and the Syrian Tatian's Diatessaron, a blending together of the Evangelists' writings, presuppose the authority enjoyed by the fourfold Gospel towards the middle of the second century. To this period or a little earlier belongs the pseduo-Clementine epistle in which we find, for the first time after II Peter, iii, 16, the word Scripture applied to a New Testament book. But it is needless in the present article to array the full force of these and other witnesses, since even rationalistic scholars like Harnack admit the canonicity of the quadriform Gospel between the years 140-175.