Lady of Shallott'
A maiden who fell in love with Sir Lancelot of the Lake, and died because her love was not returned. Tennyson has a poem on the subject; and the story of Elaine, “the lily maid of Astolat,” in the Idylls of the King, is substantially the same. (See Elaine.)
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894