Canon (Gr. a straight rod, hence a measuring rod or rule). Collections of the old Greek authors, as furnishing the rule or standard of excellence, were called models or classics. The Greek word is used in the New Testament (Gal. vi. 16, Phil. iii. 16, received text) and in the fathers to denote a rule or standard. In 2 Cor. x. 13, 15, 16, it is translated "rule" or "line," and denotes a limited part or district, as if measured off or assigned by rule. The " canonized books " or "canonical Scriptures," i. e., those admitted by the rule or furnishing the rule, were spoken of before Jerome, Augustine, and others applied the word canon directly to the books of Scripture which are received as genuine and authoritative. Jerome styled these " the holy library," and we call them "the holy Bible," or simply "the Bible." (See Bible.) From the lack of contemporary documents much obscurity rests-upon the history of the formation of the Old Testament canon. As the particular books were avowedly written at different times during a period of more than 1,000 years, each has its own history and evidence of divine authority; but a very steadfast tradition of the Jews ascribes to Ezra and " the great synagogue " the work of collecting and promulgating the Old Testament Scriptures. This tradition in its general features harmonizes with the contents of the books and the known history of •Judaism. The tradition appears, with various embellishments of detail, in the 2d (or 4th) book of Esdras (xiv. 21-48), in Tertullian, Clement of Alexandria, Irenaeus, and other early fathers, and in several books of the Talmud. The mention, in 2 Mace. ii. 13, of Ne-hemiah's gathering together in a library " the acts of the kings,.and the prophets, and of David, and the epistles of the kings concerning the holy gifts," is consistent with the idea of a gradual collection and promulgation of the sacred writings, as they then existed, during the time of Ezra and Nehemiah. All subsequent references to the Scriptures mention or presuppose the existence of the completed canon of the Old Testament. The Hebrew canon of 22 or 24 books contained all those which are now reckoned as 39. The threefold division of the Hebrew Scriptures into the law, the prophets, and.the hagiogra-pha or sacred writings (see Bible), is recognized in the prologue to Ecclesiasticus, in Philo, Josephus, the New Testament (Luke xxiv. 44), the Talmud, etc.

Philo quotes from or refers to most of the books of the Old Testament. Josephus, who says they are "justly believed to be divine," and quotes or uses all but Proverbs, Ecclesiastes, and Canticles, declares that "during so many ages as have already passed, no one hath been so bold as either to add anything to them, to take anything from them, or to make any change in them." Christ and his apostles ascribe divine authority to the Old Testament Scriptures, and the New Testament quotes all but six or seven of the 39 books of the Old Testament. The Septuagint or Alexandrine version of the Old Testament contains indeed most of what is known to us as the Apocrypha, including Es-dras, Tobit, Judith, nearly seven chapters of Esther, Wisdom of Solomon, Ecclesiasticus, Baruch, Song of the Three Children, Susannah, Bel and the Dragon, and 1, 2, and 3 Maccabees. These compositions were not, however, embraced in the Hebrew canon; were not considered by Philo, Josephus, and other Greek-speaking Jews, who used this version, as of equal authority with the law, prophets, and hagiographa; and were not quoted in the New Testament as authoritative.

Those early Christians who were unacquainted with Hebrew, and used only the Greek version, sometimes quoted and mentioned the apocryphal books as canonical; but when the subject became one of serious study, scholars generally accepted the judgment of the Jews. The most ancient Christian list, the Greek one of Melito, bishop of Sardis (about A. I). 177), mentions as the books of the Old Testament all but Ne-hemiah, Esther, and Lamentations, the first and probably the second of these being included under Ezra, and the third under Jeremiah, while he omits all the Apocrypha. With this catalogue agreed that of Gregory Nazianzen. That generally referred to Amphilochius names the same books, and says, " Besides these some admit Esther." Origen's list includes Esther and Lamentations with the other books, and (according to the present Greek text) the apocryphal Baruch. With him agree Cyril of Jerusalem and the council of Laodicea, about 363, though the canon of this council lacks authenticity. Epiphanius mentions Esther as well as "the 22 books" of the Old Testament. Athanasius puts Esther in the second rank, and retains Baruch. The apostolical canon, of uncertain date, admits three books of Maccabees, one of Judith (in some MSS.), and Esther, and recommends instruction in Ecclesiasticus. The catalogues of the Latin church exclude no books reckoned as canonical by the Hebrews; but the canon of Augustine embraces the books of Tobit, Judith, Wisdom of Solomon, Ecclesiasticus, 1 and 2 Maccabees; and the council of Hippo (393), with the third and fourth councils of Carthage (397 and 419), adopted the same enumeration.

Jerome, however, followed by a continued succession of the more learned fathers in the western church, adhered strictly to the Hebrew canon, and rejected these " ecclesiastical" or "deuterocanonical" books. "The church," said Jerome, "mayread these for the edification of the people, but not to establish the authority of the doctrines of the church." But the Roman Catholic church, following the old Latin and Septuagint versions, and the canon of Augustine, accepted as canonical, by a decree of the council of Trent (April 8, 1546), all the "ecclesiastical" books, embracing all the Apocrypha of the English Bible, except 1 and 2 Esdras and the Prayer of Manasses. The Protestant churches, on the other hand, unanimously agree with Jerome in adopting the Hebrew canon of the Old Testament, and refusing to allow any dogmatic authority to the Apocrypha. - The canon of the New Testament was formed upon substantially the same principles as that of the Old. A late and improbable tradition ascribes to the apostle John the work of collecting and sanctioning the writings worthy of being regarded as sacred; but it is now generally agreed among those who receive the Scriptures as authoritative, that the original churches, especially the larger and abler ones, collected, each for itself, a complete set of the writings that it found to be properly authenticated as the productions of apostles and other inspired men, the general accordance with one another of these numerous collections thus proving the correctness of our present New Testament canon.

That John had before him copies of the other three gospels is highly probable, his gospel being supplementary to them. That the epistles of Paul, or most of them, were early collected together, is naturally inferred from 2 Peter iii. 16, which speaks of " all his epistles," and places them on an equality with "the other Scriptures." The apostles expected their writings to be publicly read and received as of divine authority. Clement of Rome, Ignatius, Polycarp, and others, called "apostolic fathers" because contemporary with apostles, quote reverentially the gospels and all the epistles, except Jude, 2 Peter, and 3 John, though the quotations from 1 and 2 Thessalonians, Colossians, Titus, and Philemon are not decisive. The epistle to Diogne-tus, regarded as one of the earliest of uninspired Christian writings, mentions the law, the prophets, the gospels, and the apostles. Marcion's canon embraced ten Pauline epistles and a gospel mutilated from Luke's, rejecting the rest on doctrinal grounds. Theophilus often calls the New Testament writings the "holy Scriptures" or "the divine Word," and mentions the law, the prophets, and the gospels as alike divinely inspired.

Tertullian speaks of "each Testament," and distinguishes the "New Testament," made up of the "Gospels" and "Apostles," from the "Old Scripture." Irenasus also calls the New Testament writings "the holy Scriptures," or the "oracles of God," argues that there must be four gospels, and puts the evangelical and apostolic writings on an equality with the law and the prophets. The Muratorian canon (about 190), mutilated at the beginning and end, recognizes the gospels of Mark, Luke, and John, 13 epistles of Paul, 3 of John, Jude, the apocalypses of John and Peter (the latter declared not to be read in the churches by some), and omits James, Hebrews, and 2 Peter. Clement of Alexandria combines the "Apostle" (or "Apostles") and the "Gospel" as "Scriptures of the Lord" with " the law and the prophets," ratified by the authority of one almighty power. It is admitted that a Syriac version of the New Testament existed about the close of the 2d century; and there is no reason to doubt that the Peshito-Syriac version has now the same books.

This lacks 2 and 3 John, 2 Peter, Jude, and the Apocalypse, but lias all the rest of the New Testament. At the beginning of the 3d century, therefore, the four gospels, Acts, 13 epistles of Paul, and 1 John were universally received by the churches; 1 Peter was undisputed, though the meaning of the Muratorian canon is obscure; Revelation was generally received, though it was not in the Syriac version, and Dionysius of Alexandria (a disciple of Origen) with others afterward ascribed it to an unknown "John the presbyter; " the epistle to the Hebrews was generally received in the Greek and Syrian churches, its Pauline origin being disputed in the latter; James was received by the Syrian churches; Jude by the western; 2 and probably 3 John by the Greek and western; 2 Peter is not clearly mentioned in any extant writing of this date. Origen calls the collected gospels, Acts, and apostolical epistles "the New Testament," quotes as authoritative Hebrews and Revelation, mentions 1 John as of more undoubted authority than 2 and 3 John, appears fluctuating in regard to James and Jude, and names 2 Peter as doubtful. Euse-bius, the historian, in the early part of the 4th century, prepared a catalogue of the New Testament Scriptures, based upon careful investigation.

In his classification the gospels, Acts, 13 (or 14) epistles of Paul, 1 John and 1 Peter, and the Apocalypse (if authentic) are ranked as genuine and universally acknowledged. Among disputed books he mentions the epistles of James and Jude, 2 Peter, 2 and 3 John, the epistle to the Hebrews (which he elsewhere quotes as authoritative), and the Apocalypse (if not by the apostle John). He reckons as "spurious" the Epistle of Barnabas, the Shepherd' of Hennas, the Revelation of Peter, the Acts of Paul, etc. He reckons as "utterly spurious" the Gospels of Peter, Thomas, and Matthias, the Acts of Andrew, Peter, and other apostles, etc. The canon of the council of Laodicea, which, though unauthentic, belongs to this period, and the catalogues of Cyril of Jerusalem and of Gregory Nazianzen, accept all the books of our present collection except the Apocalypse. Before this, the Apocalypse had been expressly quoted as authoritative by Justin Martyr, Irenseus, Clement of Alexandria, Tertullian, Origen, Hippolytus, Methodius, and others. Athanasius and Epiphanius also include the Apocalypse with the catholic epistles and Hebrews as canonical.

The recently discovered Sinaitic MS., which is assigned to the 4th century, contains all the New Testament of our present canon, with the Epistle of Barnabas and the Shepherd of Hennas. - Small sections among the Protestants have dissented from the canon as accepted by the principal churches. The So-cinians in the 16th century, adopting methods of investigation severely critical, have thrown doubts upon several writings whose genuineness had been left unquestioned for centuries. The same process has been continued to the present day by theologians of different schools, especially in Germany. The Swedenborgians, discarding critical methods entirely, and receiving no dogmatical writing as inspired or canonical, set summarily aside the decrees of councils and the verdicts of scholars, and hold that the four gospels and the Apocalypse are the only Scriptures of the New Testament written under the full influence of the Holy Spirit. They also deny inspiration to the purely narrative and dogmatic writings of the Old Testament, Chronicles, Ezra, Nehemiah, Esther, and the books of Solomon; finding a broad line of distinction between these and the others in their doctrine of the internal sense.