Prologus Galeatus

The Prologus Galaetus or Galeatum principium (lit. and traditionally translated as "helmeted prologue" or "helmeted preface") is a preface by Jerome, dated 391-392, to his translation of the "Liber Regum" (the book of Kings composed of four parts: the first and second books of Kings and of first and second books of Samuel).
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 [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."
External links.
In English
In Latin