In ancient Greek religion and myth, Dionysus or Dionysos (/daɪ.əˈnaɪ.səs/; Greek: Διόνυσος) is the god of the grape harvest, winemaking, orchards and fruit, vegetation, fertility, insanity, ritual madness, religious ecstasy, theatre and religious mysteries. He is also known as Bacchus (/ˈbæk.əs/; Latin: Bacchus) by the Romans.