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
New Testament the Gospel of Matthew known today was composed in Greek and is neither directly dependent upon nor a translation of a text in a Semitic language. The process of canonization of the New Testament was complex and lengthy. In the initial centuries of early Christianity, there were many books widely considered by the church to be inspired, but there was no single formally recognized New Testament canon. The process was characterized by a compilation of books that apostolic tradition considered authoritative in worship and teaching, relevant to the historical situations in which they lived, and consonant with the Old Testament.