Development of the New Testament canon a novelty in Irenaeus's time. "Against Heresies" 3.11.7 acknowledges that many heterodox Christians use only one gospel while 3.11.9 acknowledges that some use more than four. The success of Tatian's Diatessaron in about the same time period is "...a powerful indication that the fourfold Gospel contemporaneously sponsored by Irenaeus was not broadly, let alone universally, recognized." Irenaeus apparently quotes from 21 of the New Testament books and names the author he thought wrote the text. He mentions the four gospels, Acts, the Pauline epistles with the exception of Hebrews and Philemon, as well as the first epistle of Peter, and
Development of the New Testament canon as are held by the smaller number and those of less authority." (On Christian Doctrines 2.12, chapter 8). Augustine effectively forced his opinion on the Church by commanding three synods on canonicity: the Synod of Hippo in 393, the Synod of Carthage (397), and another in Carthage in 419 AD (M 237-8). Each of these reiterated the same Church law: "nothing shall be read in church under the name of the divine scriptures" except the Old Testament (including the Deuterocanonicals) and the 27 canonical books of the New Testament. It seems these decrees also declared by fiat that Epistle to