Typology is an interpretive system in Christian thought wherein people, events, and passages of the Old Testament are seen as prefigurations of New Testament themes. The system is designed to prove that the New Testament is a fulfilment of the Old. The sacrifice of Isaac, for example, foretells the Crucifixion; David is a type of Christ; and the stories of Jonah and the whale and Daniel in the lions' den prefigure Christ's Passion and Resurrection. Although encountered during the early Middle Ages, typological juxtapositions become more frequent in art from the eleventh century on. See also Bible moralisée and Biblia pauperum.