Arwen was born in the year 241 of the Third Age of the Sun to Elrond Half-elven and Celebrian, daughter of Galadriel and Celeborn. She was considered the greatest beauty of her time, and it was said that the likeness of Luthien had returned to earth in her. By Elves she was called Evenstar because of her beauty, and often called Undomiel, meaning evening-maid, by Men. She lived in Rivendell and Lothlorien for nearly three thousand years, until, in the year 2951, she met Aragorn, heir of the Dunedain kingdoms. He instantly fell in love with her, and soon she returned it. In 2980, she and Aragorn were betrothed in Lothlorien, but Elrond forbade the marriage of the two until Aragorn became King.
Aragorn's deeds during the War of the Ring resulted in fulfilment of Elrond's conditions, and Arwen became Aragorn's queen. This, however, was a brave choice on Arwen's part, for it meant that in return for being with Aragorn, she had forsook the immortal life of her people and her journey to the Undying Lands; she would share the fate of Men, just as her foremother Luthien had done.
The couple had one son, Eldarion, and several daughters. They reigned happily until Aragorn's death in the year 120 of the Fourth Age. Stricken with grief at the passing of her love, Arwen said farewell to her children and passed to Lothlorien. All the Elves had left and the fair land had become cold and empty. Arwen came to the mound of Cerin Amroth, the place where she and Aragorn had been betrothed. It was here that she chose to die. And with the passing of the Evenstar, no more is said.
In the films, Arwen is played by Liv Tyler.