Dionyssos, 2009, mixed media and acrylic on canvas.

In classical mythology, Dionysus or Dionysos (pronounced /ˌdaɪ.ɵˈnaɪsəs/; Greek: Διόνυσος or Διώνυσος) is the god of wine, the inspirer of ritual madness and ecstasy, and a major figure of Greek mythology, and one of the twelve Olympians, amongst whom Greek mythology treated him as a late arrival. The geographical origins of his cult were unknown to the classical Greeks, but all myths depicted him as having "foreign" origins; Dionysus is typical of the god of the epiphany, "the god that comes".

He was also known as Bacchus, the name adopted by the Romans and the frenzy he induces, bakkheia. He is the patron deity of agriculture and the theater. He was also known as the Liberator (Eleutherios), freeing one from one's normal self, by madness, ecstasy, or wine. The divine mission of Dionysus was to mingle the music of the aulos and to bring an end to care and worry. Scholars have discussed Dionysus' relationship to the "cult of the souls" and his ability to preside over communication between the living and the dead.