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 apocrypha the message; creeds, where groups define the boundaries of interpretation of the message; and canons, which list the primary documents certain groups believe contain the message originally taught by Jesus. There was substantial debate about which books should be included in the canons. In general, those books that the majority regarded as the earliest books about Jesus were the ones included. Books that were not accepted into the canons are now termed "apocryphal". Some of them were vigorously suppressed and survive only as fragments. The earliest lists of canonical works of the New Testament were not quite the same as