Just four years after Denethor succeeded to the Stewardship, Finduilas died at a young age for one of her line. For the next thirty years, Denethor ruled as a grim and serious Steward, and it later became known that for at least some of this time, he had made use of a palantír to gain knowledge, through which the malice of Sauron had set him on the road to insanity. In the end, the death of his elder son Boromir, and the imagined loss of his younger son Faramir, sent him mad. He burned himself to death with his palantír in his hands.
Denethor II ruled as Steward for thirty-five years, and was succeeded by his younger son Faramir.