In medieval culture an accepted hierarchy of discourses set moral teaching above narrative yet established strong expectations that the two would be connected. Stories were necessary to illustrate general truths and make them memorable, while, in an age suspicious of the dangers of fiction, the claim to teach was necessary as justification for story-telling. The two most obvious forms the link could take are named in this essay's title. The exemplum has been defined as 'a short narrative used to illustrate or confirm a general statement'. Exempla or 'ensamples' usually purport to be stories that are or could be true and thus to offer evidence in support of doctrine, while 'A fable (fabula) is something which neither happened nor could happen'. Fables - invented fictions or pagan myths - were often seen as allegories, requiring interpretation to uncover a truth hidden beneath the surface. Boccaccio defines 'fabula' as 'a form of discourse, which, under guise of invention, illustrates or proves an idea; and, as its superficial aspect is removed, the meaning of the author is clear'. From early times, classical mythology had been so interpreted: Jupiter was taken to represent some aspect of the Christian God, or, as Boccaccio, following earlier commentators, explains, Mercury's visit to rebuke Aeneas means that Aeneas was roused by 'remorse, or the reproof of some outspoken friend'.