Anárion was the younger son of Elendil. He and his brother Isildur were born and raised among the Faithful in Númenor shortly before its fall. Though they were heirs of the House of Andúnië, neither ever saw their ancestral homeland, as their people had been forcibly removed to Rómenna. While in Númenor, he wed the astronomer Elennúmen, and together they had four children, the last of whom was the final man to be born upon Elenna.
When the Downfall occurred and Númenor began to be swallowed up by the sea, Elendil and his sons were prepared. In nine ships, they fled with their people to Middle-earth. With them they took heirlooms: seven Seeing Stones, the Sceptre of Annúminas, the Ring of Barahir, the sword Narsil, and the seedling of Nimloth.
Isildur and Anárion were separated from their father during the tumultuous voyage to the mainland. They landed in the south, by the mouths of Anduin, and there established the kingdom of Gondor while their father founded the kingdom of Arnor in the north. At length, their family was reunited, and though their kingdoms were far apart they kept in contact through the Seeing Stones.
Gondor was ruled jointly by the brothers, who held court in Osgiliath. Isildur settled in Minas Ithil and Anárion in Minas Anor, where he and his family knew peace for a century. Elennúmen taught their eldest daughter, Ringelenë, the ways of the stars, guiding her to become an astronomer like their parent. Almameldë became a dancer and organized many festivals in Osgiliath. Aspenindë learned healing, and her skill inspired Anárion to create the Houses of Healing where she would teach her art to all who came to learn. And his only son, Meneldil, Anárion taught to rule.
When Sauron, diminished from the fair and glorious form he had taken in Númenor, returned to the east as a shadow, he settled in Mordor and rebuilt his strength before attacking Gondor and forcing Isildur from Minas Ithil. While Anárion held Osgiliath, Isildur and his family moved north to Arnor, and aided Elendil in forming an alliance with Gil-galad, High King of the Noldor.
The Last Alliance of Elves and Men arrived in the south just in time to save Gondor from Sauron’s assault. Anárion led his people to the Dagorlad, where they laid siege to Mordor for seven years. Anárion did not live to see the end of the war; he was slain by a thrown rock a year before Sauron was defeated. In his memory, Isildur planted the seedling of the White Tree in Minas Anor and passed leadership of Gondor to Anárion’s descendants.