In Greek myth, son of Zeus and Semele, the daughter of Cadmus, king of Thebes. When Semele was made pregnant by Zeus, his jealous wife Hera, in human disguise, persuaded her to pray to Zeus to visit her in all the splendour of a god. This he did and she was consumed by his lightning; but he rescued her unborn child from the ashes and placed him in his thigh, from which in due time he was born.

The child was entrusted to Ino, sister of Semele and wife of Athamas, but Hera, still jealous, punished them by driving them mad, so that Athamas killed his son Learchos and Ino leaped into the sea with her other son Melicertes. Ino was transformed into a sea-goddess, Leucothea, and Melicertes became thc sea-god Palaemon. Dionysus was now handed over to the nymphs of Mount Nysa (variously located), whence he derived his name, where he was worshipped, and where he introduced the cultivation of the vine. He was persecuted by those who refused to recognize his divinity, but overcame them and extended his conquests far into Asia and into India. The most famous of these persecutions was that of Pentheus, king of Thebes, which forms the subject of the Bacchae of Euripides. Thc daughters of Proetus, king of Argos, also opposed him and were driven mad; their madness was cured by the intervention of the seer Melampus. Dionysus is represented as accompanied on his conquests by a host of votaries, male and female, Satyrs, Sileni, Maenads, Bassarids, dancing about him, intoxicated or possessed. They were known as Bacchi (feminine is Bacchae), sharing with the god his other name, Bacchus. The seventh Homeric Hymn relates how pirates found and kidnapped him, tying him up on shipboard; but the bonds fell off him, a vine grew about the mast, and the captive turned into a lion. The pirates in terror jumped into the sea, whereupon they were transformed into dolphins. He scarcely appears at all in Homer, and this fact, combbled with the stories of his coming to Greece from Thrace and having to overcome resistance before being accepted, has suggested to some that he was a new god, accepted late into the Greek pantheon of Olympians. However, his name has been found in Greece in the late Bronze Age on Linear B tablets, perhaps even in connection with wine, and archaeological evidence seems to suggest that he was worshipped in the island of Ceos from the fifteenth century BCE onwards; moreover, the Dionysiac festival of wine, the Anthesteria, predates the lonian migrations (in about the tenth century BCE). This evidence seems to indicate that his name and cult may be Mycenaean in origin. He is a god of an essentially different type from the Olympian deities, a giver of joy and a soother of cares (the latter described by his epithet Lyaios), experienced by the worshipper through intoxication; he is also experienced through ecstasy, felt as intensified mental power and the surrender of everyday identity. But he had another aspect, seen when his ecstatic worshippers seized a wild animal and tore it apart in order to eat it raw (the act known as sparagmos) believing that they were then incorporating in themselves the god and his power. This side of Dionysiac possession and the dire results it could lead to are often shown in the myths. Characteristic of the cult of Dionysus is the mask, symbol of the surrender of identity, and a means of transforming identity. At its simplest his image consisted of a mask on a column draped with a piece of cloth. Important in connection with his worship were the dithyramb (a variety of Greek choral Iyric poetry), tragedy, and comedy, all of which were performed at his festivals. Dionysus is frequently represented as a rather effeminate youth, with luxuriant hair, reclining with grapes or a wine-cup in his hand or holding the thyrsos, a rod with a bunch of ivy leaves fastened to the top. The Greeks identified him with the Egyptian god Osiris, and the Romans with their wine-god Liber, also called Baechus.

Dionysus, Theatre of, at Athens. The theatre at Athens was situated in the open air in a hollow on the southern slope of the Acropolis; it was within the precinct of the old temple of the god Dionysus, who thus gave the theatre its name and whose image watched over the dramatic performances of the Great Dionysia and of the Lenaea. An altar of the god stood in the centre of the dancing-floor (orchestra). The oldest remains of buildings on the site go baek perhaps to the sixth century BCE (the period of the Peisistratids). Construction of the fifth-century theatre has been attributed to Pericles.