From an Old French variant of HELEN. It appears in Arthurian legend; in Thomas Malory's 15th-century compilation 'Le Morte d'Arthur' Elaine was the daughter of Pelleas, the lover of Lancelot, and the mother of Galahad. It was not commonly used as an English given name until after the appearance of Tennyson's Arthurian epic 'Idylls of the King' (1859).