The Muratorian fragment is a copy of perhaps the oldest known list of the books of the New Testament. The fragment is a seventh-century Latinmanuscript bound in an eighth or seventh century codex that came from the library of Columban's monastery at Bobbio; it contains internal cues which suggest that it is a translation from a Greek original written about 170 or as late as the fourth century. The copy "was made by an illiterate and careless scribe, and is full of blunders" (Henry Wace). The poor Latin and the state that the original manuscript was in have made it difficult to translate. The fragment, of which the beginning is missing and which ends abruptly, is the remaining section of a list of all the works that were accepted as canonical by the churches known to its anonymous original compiler. It was discovered in the Ambrosian Library in Milan by Father Ludovico Antonio Muratori (1672 – 1750), the most famous Italian historian of his generation, and published in 1740.
The text of the list itself is traditionally dated to about 170 because its author refers to Pius I, bishop of Rome (142 - 157), as recent:
But Hermas wrote The Shepherd very recently, in our times, in the city of Rome, while bishop Pius, his brother, was occupying the chair of the church of the city of Rome. And therefore it ought indeed to be read; but it cannot be read publicly to the people in church either among the Prophets, whose number is complete, or among the Apostles, for it is after their time.
Of the General epistles, the author accepts the Epistle of Jude and says that two epistles bearing the name of John are counted in the Catholic Church; and the Book of Wisdom, "written by the friends of Solomon in his honour." The two epistles of John however are not identified further by the author, and there is no reason to assume that the John of the first letter is the same as that of the second - the church even officially regarded the canonical epistles of John as being by two different authors  (whom they named John the Evangelist and John the Presbyter, respectively). The Apocalypse of Peter is mentioned as a book which some of us will not allow to be read in church, though it is not certain whether this refers to the Greek Apocalypse of Peter or the quite different Coptic Apocalypse of Peter, the latter of which, unlike the former, was Gnostic.
↑Hahneman, Geoffrey Mark. The Muratorian Fragment and the Development of the Canon. (Oxford: Clarendon) 1992. Sundberg, Albert C., Jr. "Canon Muratori: A Fourth Century List." in Harvard Theological Review66 (1973): 1-41.
↑Metzger, The Canon Of The New Testament: Its Origin, Significance & Development (1997, Clarendon Press, Oxford).
↑Part two of the Decree of Damasus, when listing the accepted books of the New Testament, lists "of the Apostle John, one Epistle; of the other John, a Presbyter, two Epistles".