Allegory is a
story or visual image with a second distinct meaning partially hidden behind
its literal or visible meaning. The principal technique of allegory is personification, whereby abstract qualities are given human shape—as in public
statues of Liberty or Justice. An allegory may be conceived as a metaphor that
is extended into a structured system. In written narrative, allegory involves a
continuous parallel between two
(or more) levels of meaning in a story, so that its persons and events
correspond to their equivalents in a system of ideas or a chain of events external
to the tale: each character and episode in John Bunyan's The Pilgrim's Progress
(1678), for example, embodies an idea within a pre-existing Puritan doctrine of
salvation. Allegorical thinking permeated the Christian literature of the
Middle Ages, flourishing in the Morality Plays and in the Dream Visions of
Dante and Langland.