The well-known division of both Testaments into the protocanonical and deuterocanonical books seems to have first been employed by Sixtus Sennensis (1520—1569). In his Bibliotheca Sancta, Book 1. Sec. i, he writes thus: “Thus Canonical books of the first order we may call protocanonical; the Canonical books of the second order were formerly called ecclesiastical, but are now by us termed deuterocanonical.
Although retaining and making use of this nomenclature, we in no wise attribute an inferior degree of dignity to the books of the second canon; they are in such respect equal, as God is the Author of all of them. We designate by the name of protocanonical, the books concerning whose divine origin no doubts ever existed; while the deuterocanonical books are those concerning which greater or less doubts were entertained for a time by some, till finally the genuineness of the books was acknowledged, and they were solemnly approved by the Church.
The deuterocanonical books of the Old Testament are seven; Tobias, Judith, Wisdom, Ecclesiasticus, Baruch and the two books of Maccabees. Together with these, there are deuterocanonical fragments of Esther, (from the 4th verse of 1 oth chapter to 24th verse of 1 6th chapter, and Daniel III. 24-90 ; XIII, XIV.) The deuterocanonical books of the New Testament are also seven in number: The Epistle to the Hebrews, the Epistle of St. James, the, Second Epistle of St. Peter, the Second and Third Epistle/of St. John, the Epistle of St. Jude, and the Apocalypse of St. John. There are also deuterocanonical fragments of Mark, XVI. 9-20 ; Luke XXII. 43-44; and John VII. $$—VIII. 11. Many of the protestants reject all the deuterocanonical books of the Old Testament, and apply to them the term Apocryphal. It shall be a part of our labors to defend the equal authority of these books.
The Jewish mode of enumeration of their Holy Books was as arbitrary and as worthless as was their system of division. Taking twenty-two, the number of the letters their alphabet, as a number of mystic signification, they violently made the number of the Books of Holy Scripture conform thereto. Josephus makes use of this mode of enumeration. In his defense against Apion, he says: “For we have not an innumerable multitude of books among us (as the Greeks have), disagreeing from and contradicting one another, but only twenty-two books, which contain the records of all past times; which are justly believed to be divine.” [Contra Apion I. 8.] St. Jerome also, in his famous Prologus Galeatus to the Books of Kings, testifies of the existence of such number, and explains its mystic foundation: “As there are twenty-two elements, by which we write in Hebrew all that which we speak, so twenty-two volumes are computed, by which, as by letters and rudiments, the tender and suckling infancy of the just man is trained in the doctrine of God.” “And thus there are of the Old Law twenty-two books; five of Moses, eight of the Prophets, and nine of the Hagiographa. Some, however, reckon Ruth and the Lamentations among the Hagiographa, and consider that these are to be numbered in their individual number, and thus they think to be of the Old Law twenty-four books, which John personifies in the number of the twenty-four Ancients who adore the Lamb.” We see then that there were two modes of enumeration, and the Fathers confused these modes in trying to adjust their enumeration to the Jewish tradition. We cannot tell who was the first to find a mystic relation between the Greek alphabet of twenty-four letters and the twenty-four books, but it must have been done after the preponderance of the Hellenistic influence.
By separating Ruth from Judges, and the Lamentations from Jeremiah, twenty-four books resulted, and these are the books of the Jewish Canon, or as it is commonly called the Canon of Ezra, from his supposed influence upon it. As no doubts have ever arisen concerning these books, they have been called the protocanonical works or books of the First Canon. Which mode of computation is prior, it is impossible to ascertain with certainty. Loisy believes the number twenty-four to be prior, as it seems to be the Talmudic number. Against this is the authority of Josephus, who speaks of the number twenty-two as the sole traditional one. A question of so little importance may well be left in its uncertainty.
[A general introduction to the study of Holy Scriptures, A. E. Breen, pp. 243-246]
In his Bibliotheca Sancta (Tom. i. pag. 18), Sixtus distinguishes two classes of books. There he invented the terms protocanonical and deuterocanonical, and speaks of them thus: “The first class is formed of those books, which may be called protocanonical, regarding which there has never been doubt or controversy in the Catholic Church. The second class comprises the books which were formerly known as ecclesiastical, but which are now by us called deuterocanonical. These latter were not recognized by all since the times of the Apostles, but long afterward, and for this reason Catholic opinion concerning them was, at first uncertain.
The early Fathers regarded them as apocryphal and noncanonical, and only permitted them to be read to the catechumens; then with time they permitted them to be read to the faithful, not for proof of doctrine, but for edification of the faithful; and since these books were read publicly in the Church, they were called ecclesiastical. Finally, they have been placed among the Scriptures of irrefragable authority.”
Sixtus exaggerates the doubts that existed concerning the books. He was probably more conversant with Jerome than with the other Fathers, and takes him as a representative of the opinions of his time. Against his testimony stands the united testimony of the Council of Trent, composed of the greatest body of theologians ever assembled, declaring that the Church, relying on tradition, receives these books as sacred and canonical. The Council promulgated officially what had been always implicitly held. But Sixtus is disposed to accord these books a place among the canonical Scriptures on the authority of the Church. He accepts the decree, as he understands it. But the opinions of St. Jerome moved him still to reject the deuterocanonical fragments of Esther. Thus, in the aforesaid reference, he discourses of it: “The appendix of the Book of Esther, which comprises the seven last chapters, consists of various rags and patchwork, of which we find nothing in the Hebrew exemplars . . .
But it occurs to me here to admonish and entreat the good reader not to accuse me of temerity, that I cut out these seven chapters from the canonical Scriptures and place them among the apocrypha, as though I were unmindful of the decree of Trent, which, under pain of anathema, commands that all the books entire should be received, as they are read in the Church, and as they exist in the old Latin Vulgate edition.
“But that Canon is to be understood, of true and genuine parts of Scripture, pertaining to the integrity of the books, and not of certain ragged appendages, and patches rashly and disorderly tacked on by some unknown author, such as are these last chapters, which not only Cardinal Hugh, Nicolas of Lyra, and Denis the Carthusian deny to be canonical; but also St. Jerome cuts off from the volume of Esther as a spurious part, to use his own words, ‘made up of ragged fragments of words, which could be said and heard in the (several) occasions, just as it is customary for scholars to take a theme, and excogitate what words one would use, who received or wrought an injury. Origen, also, in his letter to Julius Africanus, rejects these appendages.”
Sixtus knew more of the opinions of Jerome, than of the value of oecumenical decrees. No part of the deuterocanonical books is treated so severely by Jerome as the fragments of Esther. As it was hopeless to make Jerome agree on this point with the Council, as generally understood, this avowed disciple of Jerome sought by his strange distinction to maintain the old opinion of his master. But anyone can see the flimsiness of the attempt. In fact, in the subsequent centuries, there is not found one to endorse such opinion. The words of the Council were too explicit. Every part that was in the Vulgate and read in the Church was declared sacred and canonical; the fragments of Esther fulfill both these conditions. The only way to reject deuterocanonical books and fragments is to reject the Council of Trent. In fact it is a remarkable fact, that, in the ages following the Council, Sixtus’ is the only voice raised in opposition to the equal canonicity of the books, and he only aims at these fragments. It is an evidence of the universal obedience of faith, among the children of the Church, to the voice of authority.
[ibid. pp. 523-525]