There’s St. Jerome’s prologues, for a start. When Jerome was translating OT books (because his friends kept pestering him to),
he usually prefaced them with letters addressed to one or more of his friends. That’s partly how we know which books were translated by Jerome and which were not. (That being said, out of these prologues there is one which isn’t made by Jerome:
the prologue to the Pauline epistles.)
In fact, you kinda see a progression of Jerome’s views on the deuteros if you read the prologues in chronological order. In the very first prologue he made (
the books of Samuel and Kings, AD 390) he made clear his preference for the twenty-four book Hebrew canon (= the 39 protocanonical books). Really, he tried to symbolically connect the twenty-four protocanonicals with the twenty-four elders in the book of Revelation. When he was translating the books of Solomon (Proverbs, Ecclesiastes, Song of Songs) in 398, he writes:
"Therefore, just as the Church also reads the books of Judith, Tobias, and the Maccabees, but does not receive them among the canonical Scriptures, so also one may read these two scrolls for the strengthening of the people, (but) not for confirming the authority of ecclesiastical dogmas."But by the time he translated Tobit and Judith (405-407) - the last books he translated - he had some turnaround in his opinion:
“But because this book [Judith] is found by the Nicene Council to have been counted among the number of the Sacred Scriptures, I have acquiesced to your request…”
(From the prologue to Tobit) "For the studies of the Hebrews rebuke us and find fault with us, to translate this for the ears of Latins contrary to their * canon. But it is better to be judging the opinion of the Pharisees to displease and to be subject to the commands of bishops."Jerome was a lover of Hebrew stuff, so when he began translating the OT he pretty much despised the deuteros (mainly because they’re not in Hebrew and the Jews don’t accept them

); by the middle of his task, he had warmed a bit to the books (they’re valuable and inspriring as non-Scriptural reading, but are not used for establishing doctrine), then by the end of his work he pretty much said, “Okay, fine, they’re Scripture” - because the Church accepted them.*
Great Informational Site! Thanks.