Denethor like others before him haboured resentment against the fact that they were in name only a Steward ruling "until the King returns", even as his family had been ruling Gondor for a thousand years.
When Faramir was badly wounded in the retreat from Osgiliath, Denethor stayed with him, grieving and full of regret. Driven to madness by his use of Minas Tirith's palantír and his grief, Denethor went insane. He had a pyre built in the tombs of the Stewards in Rath Dínen, intending to burn himself and his son. Faramir was saved by the intervention of Pippin, Beregond and Gandalf, but Denethor died.
In Peter Jackson's film adaptations of The Lord of the Rings, Denethor is played by John Noble.
- '"And this I remember of Boromir as a boy, when we together learned the tale of our sires and the history of our city, that always it displeased him that his father was not king. "How many hundreds of years needs it to make a steward a king, if the king returns not?" he asked. "Few years, maybe, in other places of less royalty," my father answered. "In Gondor ten thousand years would not suffice."' - J. R. R. Tolkien, The Lord of the Rings, Book 4, Chapter 5 "The Window on the West".