As told in "The Tale of Aragorn and Arwen", Aragorn in his twentieth year met Arwen for the first time in Rivendell, where he lived under Elrond's protection. Arwen, then over 2700 years old, had recently returned to her father's home after living for a while with her grandmother Lady Galadriel in Lórien. Aragorn fell in love with Arwen at first sight. Some thirty years later, the two were reunited in Lórien. Arwen reciprocated Aragorn's love, and on the mound of Cerin Amroth they committed themselves to marry one another.
After the War of the Ring, Aragorn became king of Arnor and Gondor. Arwen arrived at Minas Tirith, and they were married.
Her few appearances in the book suggest that Arwen is a minor character in The Lord of the Rings; but she serves as inspiration and motivation for Aragorn, who, as Elrond stipulated, must become King of both Arnor and Gondor before he could wed her.
The Tale of Aragorn and Arwen relates that Arwen had a son, Eldarion, and at least two unnamed daughters by Aragorn. In F.A. 121, one year after Aragorn's death, at the age of 2901 she gave up her life at Cerin Amroth.