Prologus Galeatus
The Prologus Galaetus or Galeatum principium is a preface by Jerome, dated 391–392, to his translation of the Liber Regum.
In this text, Jerome affirms his opposition to the books of the Old Testament which are outside the Hebrew canon. Jerome writes: "This prologue to the Scriptures may be appropriate as a helmeted introduction to all the books which we turn from Hebrew into Latin, so we may be able to know whatever is outside of these is set aside among the apocrypha. Therefore, Wisdom, which is commonly ascribed to Solomon, and the book of [Jesus son of Sirach], and Judith and Tobias, and The [Shepherd of Hermas|The Shepherd] are not in the canon. I have found the First Book of the Maccabees Hebrew, the Second is Greek, which may also be proven by their styles."
About the Hebrew canon
In this prologue Jerome mentioned the grouping, number, and order of the Hebrew Bible:- Law consists five books: Genesis, Exodus, Leviticus, Numbers, Deuteronomy
- Prophets consists eight books: Joshua, Judges, Samuel, Kings, Isaiah, Jeremiah, Ezekiel, Twelve Prophets
- Hagiographa consists nine books: Job, Psalms, Proverbs, Ecclesiastes, Song of Songs, Daniel, Chronicles, Ezra, Esther