Aragorn is a descendant of Elendil and Isildur, and heir of the Kingships of Arnor and Arthedain, and Chieftain of the Dúnedain (known as "Rangers" in Eriador). He was born in T.A. 2931 as the son of Arathorn and Gilraen. After his father was killed by orcs, Gilraen and her son moved to Rivendell, where Aragorn was raised unaware of his heritage under the name Estel (Sindarin: "hope"). Upon coming of age, he was told by his foster-father Elrond of his heritage, and given the heirlooms of the shards of Narsil and the Ring of Barahir. Shortly after, he met Elrond's daughter Arwen for the first time and fell in love with her. In the following years, Aragorn became friends with Gandalf and set out on many adventures of knights-errantry under various names, serving in Rohan and Gondor under the name Thorongil.
War of the Ring
During the story told in the The Lord of the Rings, Aragorn met Frodo Baggins and the hobbits in Bree, where he was known as Strider. Gandalf had left a letter for Frodo which told him to trust Aragorn, who led the hobbits to Rivendell. After the Council of Elrond, Aragorn became a member of the Fellowship of the Ring. Before they set out, the shards of Narsil were reforged, and Aragorn named the sword Andúril. He led the Fellowship after the loss of Gandalf. After the Breaking of the Fellowship, Aragorn, Legolas and Gimli followed the orcs into Rohan. They were found by Gandalf in Fangorn Forest, who then brought them into the war of Rohan against Saruman.
After the War of the Ring, Aragorn was crowned King of the Reunited Kingdom of Arnor and Gondor, and took up the name Elessar Telcontar. He kept the office of the Steward, again rewarding it to Faramir, in addition to making him Prince of Ithilien. Aragorn wedded Arwen, with whom he had a son, Eldarion, and several daughters. Aragorn died peacefully on March 1st of the year 120 of the Fourth Age, and was succeded by his son Eldarion.
It is his return as King that is referred to in the title of the third volume of The Lord of the Rings. The "return of the king" itself is an event of myth, not expected by anyone. In the lands formerly under the rule of Arnor, the people retained only a distant memory, remaining in sayings and idioms such as somebody having "never heard of the king" if behaving badly or against the rules. In Gondor the line of Anárion had stopped with the last King Eärnur, who was succeded by his Steward. The Stewards of Gondor ruled in the King's name, but the return of a king was no longer an anticipated event, merely a story.
- J. R. R. Tolkien, The Lord of the Rings, Appendix A, The Tale of Aragorn and Arwen