Tragedy, a form of drama central to western literature, dates to ancient times—the fifth century B.C., when Greeks held a religious festival to honor the god Dionysus (god of fertility, wine, and, later, drama). Famous ancient tragedies include Oresteia by Aeschylus (who is credited with inventing tragedy), Oedipus Rex by Sophocles, and Medea and Trojan Women by Euripides. The philosopher Aristotle observed that tragedy’s function is a cathartic one—by participating in the drama, the spectators are purged of their emotions of pity and fear. The well-known Renaissance tragedies of William Shakespeare (1564–1616) harken back to the works of Roman statesman and playwright Seneca (c. 4 B.C.-A.D. 65), who wrote during the first century. He is credited with creating dramatic conventions including unity of time and place, violence, bombastic language, revenge, and ghostly appearances.