Aragorn and Elrond
Aragorn, son of Arathorn, was only two years old when his father was slain by an orc-arrow. His mother Gilraen then brought him to the house of Elrond in Rivendell, where the Half-elven lord took the place of his father and came to love him as a son of his own. For reasons of safety—for the Wise knew that the Enemy was seeking to discover the Heir of Isildur—Aragorn's true name and lineage were kept secret, and he was called Estel, the Hope. He grew up in Elrond's household, unaware of his heritage until he was twenty years old.
The Revelation of Identity and the Heirlooms
When Estel returned to Rivendell after great deeds in the company of Elrond's own sons, Elladan and Elrohir, Elrond looked at him and was pleased, seeing that he was fair and noble and early come to manhood. That day Elrond called him by his true name, Aragorn, and told him who he was and whose son. He delivered to him the heirlooms of his house: the Ring of Barahir, the token of their kinship from afar, and the shards of Narsil, the sword of Elendil. Elrond foretold that the span of Aragorn's life would be greater than the measure of Men, unless evil befell him or he failed at the test, but he withheld the Sceptre of Annúminas, saying that Aragorn had yet to earn it.
The Shadow of Arwen and the Doom of Parting
The relationship was profoundly complicated by Aragorn's love for Elrond's daughter, Arwen. When Aragorn first saw her in the woods of Rivendell, he called her Tinúviel, believing her to be Lúthien herself. Elrond, perceiving what had happened, summoned Aragorn and spoke gravely. He told Aragorn that a great doom awaited him, either to rise above the height of all his fathers or to fall into darkness. He forbade Aragorn to bind any woman to him in troth until his time came, and specifically warned him against Arwen, who was of lineage greater than his and had lived in the world so long that to her he was but a yearling shoot beside a young birch. Elrond revealed the doom laid on his house: that so long as he abode in Middle-earth, Arwen would live with the youth of the Eldar, and when he departed, she would go with him. Aragorn, with the foresight of his kindred, understood that the choice would soon be laid on Elrond's children to part either with him or with Middle-earth. Elrond acknowledged this, but said that there would be no choice for Arwen unless Aragorn came between them and brought one of them to a bitter parting beyond the end of the world.
The Long Years of Errantry and the Final Test
Aragorn took leave of Elrond and went out into the wild for nearly thirty years, labouring in the cause against Sauron. He became a friend of Gandalf and won renown under many names, serving in the host of the Rohirrim and fighting for the Lord of Gondor. When he returned to Rivendell weary from his perils, he found Arwen there again, and on the hill of Cerin Amroth in Lothlórien they plighted their troth. Elrond, learning of this, was silent, though his heart was grieved. He told Aragorn that Arwen should not diminish her life's grace for less cause than to be the bride of the King of both Gondor and Arnor. The victory of the War of the Ring, Elrond said, could bring him only sorrow and parting, but to Aragorn hope of joy for a while. At the end of the Third Age, when the Great Ring was unmade and the Three Rings were shorn of their power, Elrond grew weary at last and forsook Middle-earth, never to return. He surrendered the Sceptre of Annúminas to Aragorn at his crowning, and laid the hand of his daughter in the hand of the King, fulfilling the long tale of their waiting and labours. Yet the parting between Elrond and Arwen was sundered by the Sea and by a doom beyond the end of the world, a sorrow that Elrond had foreseen from the very beginning of his foster-son's love for his daughter.