Aman, accessible to the Elves but not to mortals, persisted. Númenor was utterly destroyed, as was the fair body of Sauron; however, his spirit returned to Mordor, where he again took up the One Ring, and gathered his strength once more. Elendil, his sons and the remainder of the Faithful sailed to Middle-earth, where they founded the realms in exile of Gondor and Arnor. Sauron arose again and challenged them. The Elves allied with Men to form the Last Alliance of Elves and Men. For seven years, the Alliance laid siege to Barad-dûr, until at last Sauron himself entered the field. He slew Elendil, High King of Gondor and Arnor, and Gil-galad, the last High King of the Noldor in Middle-earth. However, Isildur took up the hilt of Narsil, his father's shattered sword, and cut the One Ring from Sauron's hand. Sauron was defeated, but not utterly destroyed. Afterward, Isildur ignored the counsel of Elrond, and rather than destroy the One Ring in the fires of Mount Doom, he kept it as weregild for his dead father. But the Ring betrayed him and slipped from his finger as he was escaping from an Orc ambush at the Gladden Fields. Isildur was killed by an orc arrow, and the Ring was lost in the Anduin River. Third Age The Third Age lasted for 3021 years, beginning with the first downfall of Sauron, when he was defeated by the Last Alliance of Elves and Men following the downfall of Númenor and ending with the War of the Ring and final defeat of Sauron, the events narrated in The Lord of the Rings. Virtually the entire history of the Third Age takes place in Middle-earth. The Third Age saw the rise in power of the realms of Arnor and Gondor, and their fall. Arnor was divided into three petty Kingdoms, which fell one by one in the wars with Sauron's vassal kingdom of Angmar, whilst Gondor fell victim to Kin-strife, plague, Wainriders, and Corsairs. In this time, the line of the Kings of Gondor ends, with the House of the Stewards ruling in their stead. Meanwhile, the heirs of Isildur from the fallen kingdom of Arnor wander Middle-earth, aided only by Elrond in Rivendell; but the line of rightful heirs remains unbroken throughout the age. This age was characterized by the waning of the Elves. In the beginning of the Third Age, many