§ Of the Rings of Power and the Third Age The Silmarillion

Thus began the Third Age of the World, after the Eldest Days and the Black Years; and there was still hope in that time and the memory of mirth, and for long the White Tree of the Eldar flowered in the courts of the Kings of Men, for the seedling which he had saved Isildur planted in the citadel of Anor in memory of his brother, ere he departed from Gondor. The servants of Sauron were routed and dispersed, yet they were not wholly destroyed; and though many Men turned now from evil and became subject to the heirs of Elendil, yet many more remembered Sauron in their hearts and hated the kingdoms of the West. The Dark Tower was levelled to the ground, yet its foundations remained, and it was not forgotten. The Númenóreans indeed set a guard upon the land of Mordor, but none dared dwell there because of the terror of the memory of Sauron, and because of the Mountain of Fire that stood nigh to Barad-dûr; and the valley of Gorgoroth was filled with ash. Many of the Elves and many of the Númenóreans and of Men who were their allies had perished in the Battle and the Siege; and Elendil the Tall and Gil-galad the High King were no more. Never again was such a host assembled, nor was there any such league of Elves and Men; for after Elendil’s day the two kindreds became estranged.