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 Westcott-Hort, von Soden, Vogels, Merk, Bover and Nestle-Aland), concluding that 62.9%, or 4999/7947, are in agreement. They concluded, "Thus in nearly two-thirds of the New Testament text, the seven editions of the Greek New Testament which we have reviewed are in complete accord, with no differences other than in orthographical details (e.g., the spelling of names). Verses in which any one of the seven editions differs by a single word are not counted. ... In the Gospels, Acts, and Revelation the agreement is less, while in the letters it is much greater" Per Aland and Aland, the total consistency achieved