The Bacchanalia were an ancient Greek cult of Dionysus widespread across Italy. The Roman senate issued a decree against it, probably for political rather than religious reasons.
Bouchard, Elsa. "Prohibition of the Bacchanalia in Rome". The Literary Encyclopedia. First published 01 March 2010
[http://www.litencyc.com/php/stopics.php?rec=true&UID=11366, accessed 21 December 2013.]