A celebration named after Bacchus, the Roman god of wine, drukness and intoxication (Dionysus in Greek mythology). These events are often characterized as a drunken orgies and began around 200 BCE. 

Bacchus was the god of the grape harvest, winemaking and wine, of ritual madness and ecstasy in Greek mythology. From the god of wine called Bacchus, came forth a celebration known as Bacchanal or Bacchanalia. 

She also ordered the festivities to take place by night (in the time of dark) instead of by day, and decided that instead of taking place over three days in a year there would be five days of initiation in each month. Participants of the ceremonies were to be of all sorts: men and women, noble and common people, free and slaves—all in a celebration of wine and sex.

The rites gradually turned into sexual orgies, wild parties etc. Those among the men, and men who refused to take part were sacrificed. It is said these men were fastened to a machine and taken to hidden caves, where it was claimed they were kidnapped by the gods.

Today you can still see the influence of Bacchanalia festival in wild parties, orgy parties, group sex and swingers parties.

Read also the article called “Maenad” being the gods of unrestrained behaviors of wild dancing, drunkness etc.