C. F. Keil and Franz Delitzsch on 1 Kings 11:41-43

1Ki 11:41-43 Conclusion of the history of Solomon. - Notice of the original works, in which further information can be found concerning his acts and his wisdom (see the Introduction); the length of his reign, viz., forty years; his death, burial, and successor. Solomon did not live to a very great age, since he was not more than twenty years old when he ascended the throne. -  Whether Solomon turned to the Lord again with all his heart, a question widely discussed by the older commentators (see Pfeifferi Dubia vex. p. 435; Buddei hist. eccl. ii. p. 273ff.), cannot be ascertained from the Scriptures. If the Preacher Koheleth) is traceable to Solomon so far as the leading thoughts are concerned, we should find in this fact an evidence of his conversion, or at least a proof that at the close of his life Solomon discovered the vanity of all earthly possessions and aims, and declared the fear of God to be the only abiding good, with which a man can stand before the judgment of God.