Prologus Galeatus

[4] In this text, Jerome affirms his opposition to the books of the Old Testament which are outside the Hebrew canon.

[3][5] Jerome writes: "This prologue to the Scriptures may be appropriate as a helmeted introduction [galeatum principium] 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 are not in the canon.

I have found the First Book of the Maccabees (is) Hebrew, the Second is Greek, which may also be proven by their styles.

"[6] In this prologue Jerome mentioned the grouping, number, and order of the Hebrew Bible:[5] When he counted, the books of Samuel, Kings, and Chronicles were not divided in two.

Extract from the preface, with the passage which gave it its nickname underlined in red, in the Patrologia Latina , v. 28.