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 seems that not always have all of these been considered on the same level as the others, yet nevertheless these also have been counted and reckoned with the rest of Scripture, both by Synods and by many of the most ancient and eminent Theologians of the Catholic Church. All of these we also judge to be Canonical Books, and confess them to be Sacred Scripture..." Development of the New Testament canon The canon of the New Testament is the set of books Christians regard as divinely inspired and constituting the New Testament of the Christian Bible. For most, it is