Bacchus, in classical mythology, the god of wine, known among the Greeks as Dionysus, and often called by the Romans Liber. He was the son of Jupiter and Semele, the daughter of King Cadmus. Juno avenged herself by visiting Semele in disguise, and inducing her to demand of Jupiter that he should appear before her clothed in the attributes of his majesty. No mortal could bear this sight, and Semele was destroyed. Jupiter, however, preserved the still-born child, enclosed him in his own thigh until the proper period for birth, and gave him to the sister of Semele and her husband, and, when Juno persecuted these, to the nymphs, for education. The nymphs brought him up at Nysa in Thrace, where Silenus also assisted in teaching him. Bacchus taught men the cultivation of the vine and the art of wine-making. He collected bands of worshippers, principally women, and surrounded by these, and seated in a chariot drawn by panthers or leopards, he passed through many countries, and even penetrated to India. His followers, maddened with wine and license, and carrying the thyrsus, a hollow wand twined with ivy and vine leaves, attacked those even of their own families who resisted the introduction of the new religion.

Pentheus of Thebes was thus killed by his own mother, who was among the Bacchantes. - The Greek legends of the adventures of the god were almost innumerable. He iiayed Damascus alive, who opposed him in Syria; visited Lycurgus, king of the Edones, with madness in which he killed his own son; and after the king again became sane, caused him to be torn in pieces by wild horses. He overcame the Amazons. Carried off to sea while he slept by a party of sailors who purposed selling him as a slave in Egypt, he caused the vessel to stand still while vines and ivy grew around the mast and spars, and wine flowed from the deck; then he assumed the form of a lion, and afterward of a bear, killed the captain, and changed the seamen into dolphins, preserving only the pilot, who had warned the crew against molesting the god. The traditions concerning him are very differently given by different authors. Even concerning his birth the legends were contradictory, while the methods of his worship in different countries were widely at variance. He was represented in some works of art as an infant, but generally by the Greeks as a beautiful boy; while in the East he was pictured as a man of middle age and majestic figure, clothed in long robes.

His festivals and religious rites, which, originating in Thrace, became wild orgies and scenes of license in Greece and Rome (see Bacchanalia), and were finally suppressed in the latter city, were probably originally simple ceremonies in honor of the rich and productive power of nature, which he, as god of wine, undoubtedly represented. Among the powers which were attributed to Bacchus were those of prophecy, of healing certain diseases, and of increasing the productiveness of the earth.