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 among Protestants when referring to those books found in the Christian Old Testament although not in the Jewish Bible, modern scholars began to refer to these works of early Christian literature not included in the New Testament as "apocryphal", by which was meant non-canonical. Collected editions of these works were then referred to as the "New Testament apocrypha". Typically excluded from such published collections are the following groups of works: The Apostolic Fathers, the 2nd-century Christian apologists, the Alexandrians, Tertullian, Methodius of Olympus, Novatian, Cyprian, martyrdoms, and the Desert Fathers. Almost all other Christian literature from the period, and sometimes