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
Jewish–Christian gospels gospels as follows: The Jewish–Christian gospels are known through quotations in the works of the early Church Fathers Clement of Alexandria, Origen, Eusebius, Epiphanius, Jerome and probably Didymus the Blind. These all assumed that only one Jewish Christian gospel existed, although in various versions and languages, which they attributed to well-known sects such as the Ebionites and Nazarenes. The majority of critical scholars have rejected this view and identify at least two and possibly three separate Jewish–Christian gospels. The standard collection of the Jewish–Christian gospels is found in Schneemelcher's "New Testament Apocrypha"; Schneemelcher, following Hans Waitz, groups the extant sayings