In Greek mythology, Dionysus was the Olympian god also called Bacchus by the Romans.
Dionysus governed wine, winemaking, theatre, ritual madness, fertility, and ecstatic celebration. His worship involved music, dance, dramatic performance, and altered states of consciousness. Ancient Greek theatre developed in connection with festivals held in his honor, especially the Dionysia at Athens.
Dionysus was the son of Zeus and the mortal woman Semele in the best-known tradition. After Semele died before his birth, Zeus carried the unborn child in his thigh until Dionysus could be born. This unusual story helped explain the god’s epithet “twice-born.”
The Roman name Bacchus is often used for Dionysus, although Liber was another Roman deity closely associated with him. Dionysus was accepted among the Olympians in traditions that counted him as one of the twelve.