New Testament document, in addition to some other sources, to write their individual gospel accounts. These three gospels are called the Synoptic gospels because they include many of the same stories, often in the same sequence, and sometimes exactly the same wording. Scholars agree that the Gospel of John was written last, by using a different tradition and body of testimony. In addition, most scholars agree that the author of Luke wrote the Acts of the Apostles. Scholars hold that these books constituted two halves of a single work, Luke-Acts. Strictly speaking, each gospel and the book of Acts is arguably anonymous.
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