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
Historical reliability of the Gospels intention and genre, gospel sources and oral tradition, textual criticism, and historical authenticity of specific sayings and narrative events. The genre of the gospels is essential in understanding the intentions of the authors regarding the historical value of the texts. New Testament scholar Graham Stanton states that "the gospels are now widely considered to be a sub-set of the broad ancient literary genre of biographies." Charles H. Talbert agrees that the gospels should be grouped with the Graeco-Roman biographies, but adds that such biographies included an element of mythology, and that the synoptic gospels also included elements of mythology. E.P.