Heidegger's Bible Handbook: Proverbs: Canonical Authority
4. Concerning the authority of the book, the heresy of Theodore of Mopsuestia and of the Ancient Talmudists is refuted.
Concerning the authority of the book, whether it be Divine and Canonical, or human, it has been called into question of old by impudent men. Indeed, Theodore of Mopsuestia taught that Solomon dictated Proverbs only in human wisdom, and that he did not receive the grace of Prophecy when he wrote them: therefore, at the fifth Synod of Constantinople in 551 AD he was marked with obloquy. The ancient Talmudists also write: ספר משלי בקשו לגנון שהיו דבריו כותרין זח את זה, (some) wished ἀποκρύπτειν, to hide, the Book of Proverbs, because its words fight amongst themselves. But the conjectures of this their attempt the Celebrated Hottinger, in his Thesauro Philologico, book II, chapter 1, Section 3, learnedly sets forth. And concerning the rest among all, Hebrews and Greeks, and the orthodox Latins, even indeed the heterodox and heretics, the divine authority of this book was placed beyond all occasion of doubt. And the sort and efficacy of the doctrine directing to Christ and a holy life, all the other seals of Divinity, and especially its oft repeated use by Christ and the Apostles, most clearly confirm it.
 Theodore (c. 350-428) served as Bishop of Mopsuestia in Asia Minor. Although much of his work has been lost, what remains is a monument of early Antiochene exegesis, characterized by careful consideration of, and adherence to, grammar and history.  That is, the Fifth Ecumenical Council, the second at Constantinople.
Dr. Dilday's Lecture: "Proverbs, Part 2"