What were the differences among mystery plays, miracle plays, and morality plays?

In the context of Western literature, mystery, miracle, and morality plays represent the three primary forms of medieval vernacular drama. While all three emerged from religious roots, they differed significantly in subject matter and structure.123

• Mystery plays focused on biblical subjects, ranging from the Creation to the Last Judgment. Originally performed by churchmen, they were later produced by guilds in elaborate cycles, often using pageant wagons to depict various scenes.2
• Miracle plays centered on the lives, martyrdoms, or miracles of saints, particularly the Virgin Mary or St. Nicholas. These plays evolved from liturgical festivals and often featured the saint intervening in human affairs to provide aid or salvation.1
• Morality plays were allegorical dramas that dramatized the human struggle between virtue and vice. Unlike the others, they focused on abstract characters—such as Mankind or the Seven Deadly Sins—to teach moral lessons about the choice between good and evil and the inevitability of death.43

These genres collectively bridged the gap between early liturgical ceremonies and the rise of professional, secular theatre.435