Isildur - in The Lord of The Rings

In The Lord of The Rings

As detailed in the appendices of The Return of the King, Isildur was born in the year 3209 of the Second Age in Númenor, the first son of Elendil son of Amandil, the last Lord of Andúnië. He had a younger brother, Anárion. Isildur had four sons: Elendur, Aratan, Ciryon, and Valandil.

In Isildur's youth, Númenor's King Ar-Pharazôn was corrupted by Sauron, who urged the White Tree to be cut down. Isildur went to the courts of the king in disguise and stole a fruit of Nimloth, though the guards were alerted and he was severely wounded in his escape. He was badly wounded, but his sacrifice was not in vain; Nimloth was cut down and burned shortly afterwards, but the line of the White Tree continued.

The Silmarillion explains that Isildur, together with his father and brother, fled when Númenor was destroyed by Ilúvatar. Elendil landed in the north, founding the realm of Arnor, while Isildur and Anárion landed in the south and established the realm of Gondor, which they ruled jointly until Anárion was killed in Mordor.

Isildur settled on the east bank of the Anduin and established the city of Minas Ithil (which would later be named Minas Morgul), as well as the province of Ithilien and setting his throne alongside his brother Anárion in the city of Osgiliath. However, in 3429 (see the Appendix of The Return of the King, especially the chronology of the Second Age) Sauron captured Minas Ithil and destroyed the White Tree. Isildur and his family escaped down the Anduin by boat, bearing with them a seedling of the tree. They sailed to Lindon, seeking the Elven High King Gil-galad and Elendil in Arnor. Meanwhile, Anárion bought time for Gondor by defending Osgiliath and driving the Dark Lord back to the mountains, while Elendil and Gil-galad marshalled their forces.

As told in The Fellowship of the Ring, he returned with his father and Gil-galad in the Last Alliance of Elves and Men in 3434. After the Alliance was victorious over Sauron's host at the Battle of Dagorlad, they advanced into Mordor and laid siege to Barad-dûr. When Minas Ithil was recaptured, Isildur sent his younger sons Aratan and Ciryon to man that fortress, which would prevent Sauron and his forces from escaping that way. Isildur was accompanied throughout the war by his eldest son Elendur. The campaign in Mordor was long and bitter, and Anárion was slain by a stone from the Dark Tower.

After seven years of besieging the Dark Tower, the enemy was all but defeated and Sauron appeared to challenge the king. During the final battle on the slopes of Mount Doom, Elendil and Gil-galad were both slain in combat with the Dark Lord, but Sauron's mortal form was slain as well. Isildur took the hilt-shard of his father's sword Narsil, which had broken beneath Elendil when he fell, and cut the One Ring from Sauron's hand; causing Sauron's malignant spirit to flee.

Despite the urging of Elrond and Círdan, Gil-galad's lieutenants, Isildur did not throw the Ring into the fires of Mount Doom; Instead, he claimed it as an heirloom for his House, and as weregild for the deaths of his father and brother.

After the fall of Sauron, the greater part of the army of Arnor returned home while Isildur stayed in Gondor for a year, restoring order and defining its boundaries. He planted the seedling of the White Tree in Minas Anor in memory of Anárion. As his brother's helm had been crushed during his death at Barad-dûr, Isildur left his helm from the overthrow of Sauron as the replacement for Gondor's crown. He placed Anárion's son Meneldil in charge of Gondor, and returned north to Arnor with his three sons. His wife and fourth son Valandil had stayed behind in Rivendell throughout the War of the Last Alliance and the aftermath, and Isildur also sought further counsel from Elrond.