In Roman legend, Bacchus stepped in for Dionysus, and earned the title of party god. In fact, a drunken orgy is still called a bacchanalia, and for good reason. Devotees of Bacchus whipped themselves into a frenzy of intoxication, and in the spring Roman women attended secret ceremonies in his name. Bacchus was associated with fertility, wine and grapes, as well as sexual free-for-alls. Although Bacchus is often linked with Beltane and the greening of spring, because of his connection to wine and grapes he is also a deity of the harvest.
Bacchus has a divine mission, and that is his role of "liberator." During his drunken frenzies, Bacchus loosens the tongues of those who partake of wine and other beverages, and allows people the freedom to say and do what they wish. In mid-March, secret rituals were held on Rome's Aventine hill to worship him. These rites were attended by women only, and were part of a mystery religion built up around Bacchus.
In addition to being the patron of wine and drink, Bacchus is a god of the theatrical arts. In his incarnation as the Greek Dionysus, he had a theater named for him in Athens. He is often portrayed as a slightly effeminate figure, prone to good humor and general bawdiness.
Bacchus was the son of Jupiter, and is often portrayed crowed with vines or ivy. His chariot is drawn by lions, and he is followed by a group of nubile, frenzied priestesses known as Bacchae. Sacrifices to Bacchus included the goat and the swine, because both of these animals are destructive to the annual grape harvest -- without grapes, there can be no wine.