Cardinal Cajetan was a contemporary of Luther and held with high regard in the Roman Catholic Church.
"The papal legate, Cajetan, and Luther met face to face for the first time at Augsburg on 11 October. Cajetan (b. 1470) was "one of the most remarkable figures woven into the history of the Reformation on the Roman side . . . a man of erudition and blameless life" (Weizacker); he was a doctor of philosophy before he was twenty-one, at this early age filling chairs with distinction in both sciences at some of the leading universities; in humanistic studies he was so well versed as to enter the dialectic arena against Pico della Mirandola when only twenty-four. Surely no better qualified man could be detailed to adjust the theological difficulties."
Writing prior to the canon decision at the Council of Trent, Cajetan wrote:
"Here we close our commentaries on the historical books of the Old Testament. For the rest (that is, Judith, Tobit, and the books of Maccabees) are counted by St Jerome out of the canonical books, and are placed amongst the Apocrypha, along with Wisdom and Ecclesiasticus, as is plain from the Prologus Galeatus. Nor be thou disturbed, like a raw scholar, if thou shouldest find anywhere, either in the sacred councils or the sacred doctors, these books reckoned as canonical. For the words as well of councils as of doctors are to be reduced to the correction of Jerome. Now, according to his judgment, in the epistle to the bishops Chromatius and Heliodorus, these books (and any other like books in the canon of the bible) are not canonical, that is, not in the nature of a rule for confirming matters of faith. Yet, they may be called canonical, that is, in the nature of a rule for the edification of the faithful, as being received and authorised in the canon of the bible for that purpose. By the help of this distinction thou mayest see thy way clearly through that which Augustine says, and what is written in the provincial council of Carthage."
-Cardinal Cajetan (16th century)
Cajetan recognized that though the deuterocanonicals may be called canonical, they were not recognized as canonical in the same sense as the other Old Testament books.