An allegory is a narrative having a second meaning beneath the surface one - a story with two meanings, a literal meaning and a symbolic meaning. Examples of allegories are the Fairie Queen by Edmund Spenser, Pilgrim's Progress by John Bunyan and Young Goodman Brown by Nathaniel Hawthorne An example of an Allegory can be found in the poetic work of Edmund Spenser . The Faerie Queene by Edmund Spenser Lo I the man, whose Muse whilome did maske, As time her taught, in lowly Shepheards weeds, Am now enforst a far vnfitter taske, For trumpets sterne to chaunge mine Oaten reeds, And sing of Knights and Ladies gentle deeds; Whose prayses hauing slept in silence long, Me, all too meane, the sacred Muse areeds To blazon broad emongst her learned throng: Fierce warres and faithfull loues shall moralize my song. Excerpt from Book 1

An Allegory is a poem, a play or a picture etc in which characters, actions and even objects are used to symbolize a moral, social, political or spiritual meaning. Characters can be personifications of abstract ideas like charity, greed or envy. Therefore there can be and most often is in literature more than one symbol.

http://dictionary.reference.com/browse/allegory http://en.wikipedia.org/wiki/Allegory