Elrond was the son of Eärendil and Elwing and the brother of Elros. He was an Elf, born in the First Age, at the end of which he was granted to choose between being a Man or an Elf, and choosing to be an Elf became an Elven-lord of great power and wisdom.
Until 1695 of the Second Age Elrond dwelt with Gil-galad in Lindon. However, in 1695 he was sent to Eregion to defend that place against Sauron. Eregion was overrun by Orcs in 1697, and thus Elrond fled north and founded Rivendell, which became a great Elven stronghold. During the War of the Last Alliance Elrond served as the herald of Gil-galad and was with him when he was slain.
In 100 of the Third Age Elrond married Celebrían, who bore to him Arwen Evenstar, Elladan and Elrohir. Elrond always gave aid to the Dúnedain, especially the line of Isildur, both militarily and knowledge-wise. Elrond bore the greatest of the Elven Rings, Vilya, and it went with him when he sailed over the Sea at the end of the Third Age.