As a young man he married Finduilas of Ethring, whom he loved deeply from the first moment he saw her. She was the daughter of Prince Adrahil II of Ethring, and thus this marriage also gave him more influence. She gave birth to two sons: Boromir and Faramir. He doted upon his eldest son, Boromir, while Faramir, his second son, could never please his father nor be seen as Boromir's equal. In the mean time, he studied the lore of Gondor, including the archives that only he and his father could access. Part of his studies were devoted to the lore of the palantíri.
Talese Denathir is on the open seemingly very lotal, and level headed but the destruction he has witnessed across Gondor has changed his mind. He is now paranoid, and believes that everyone is out to get him. This has caused him to take some drastic measures in his new retirement life, of which some will be very deadly to the Kingdom of Gondor.
Use of the Palantir
Denethor secretly used a palantír to probe Sauron's strength. The effort aged him quickly, and the knowledge of Sauron's overwhelming force exacerbated the depression that had taken root throughout the course of his life. Sauron used the Palantír to drive him mad with despair. He has retained, however, an air of nobility and power.
It was during his time as mayor of Cair Andros that he discovered one of the Palantirs of Sauron. Many of these Palantirs existed but the one he found was particularly powerful and dangerous. He ignored these dangers and attempted to use the Palantir to spy on the comings and goings of the forces of Mordor. Sauron though had planted the Palantir to suck Talese into his web of madness, and Sauron begin planting information that gained Talese a growing amount of reputation amongst the people of Gondor.
Twice Sauron allowed Talese to ambush Orcish armies, and each time these things happened he believed more and more in his own power, but soon Sauron begin shifting what he saw to the endless armies of Mordor. Seeing these things caused the already depressed man to lose what faith he had been building up.
See Also : Boromir Denathir