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
Oxyrhynchus Gospels and Luke 9:50, but the differences in phrasing show they are textually independent of the Gospels. A precise date for composition is unknown; 50 is possible, though a date of around 150 AD. is more widely accepted by scholars. John Dominic Crossan notes the mutilated condition in his introduction to the fragmentary text in "The Complete Gospels" resulting in highly conjectural reconstructions of the text, which, however, "does not seem to be dependent on the New Testament gospels... As an independent gospel, it belongs, insofar as its fragmentary state allows us to see, not with discourse gospels involving the risen