Originally, all drama was written in verse. The Graeco-Roman models on which subsequent dramas were based were all composed in verse, having evolved out of choral performances that were originally sung to musical accompaniment. The medieval mystery and miracle plays were also in verse and intended to be easily memorable for illiterate audiences, often as a pedagogical device. Most Renaissance drama was primarily written in verse, although rustics were occasionally assigned prose passages. Prose became a significant dramatic medium in the comedy of the 18th century Restoration, where it was used to imitate natural speech. Prose passages within dramas or prose dramas signify some form of realism, or occasionally pedestrian or mundane or vulgar subject matter not suitable to the elevated nature of verse.