(Also Fauna, Damia)
"The Good Goddess"
In Roman mythology, Bona Dea was a goddess of fertility and virginity who was especially worshipped by the Roman matrons. She was also associated with healing the sick, and those women suffering from illness would be taken care of by priestesses in the medicinal herb gardens outside of her temples. A daughter (or sometimes wife or sister) of Faunus, she antedated Venus in the Roman religion.
Bona Dea was often depicted on Roman coins sitting in a throne and holding a cornucopia. She was associated with coins and also snakes, which represented healing and my have indicated a phallic nature to her cult (consecrated snakes were allowed to roam freely throughout her temple). When she appeared to humans, it was either as a beautiful young woman or an old woman with pointed ears, who was holding a snake in one hand.
The worship of Bona Dea was limited exclusively to women, with even paintings or drawings of men or male animals being prohibited. Also forbidden were the words 'wine' and 'myrtle' because Bona Dea’s deification was brought about after Faunus tried to seduce the goddess. When she resisted, he made her drunk with wine and whipped her with a myrtle branch in an attempt to force her into having relations. He succeeded only after turning himself into a snake, killed her and turned her into a goddess. Another version holds that Bona Dea, Faunus's wife became drunk too often for her husband’s liking and so he killed her in anger and thus she was made into a goddess.
Her temple was located under a large overhanging rock on the Aventine hill. The temple was decorated with vines and flowers, and though it was not permissible to speak the word, wine was served in a jar referred to as a honey-pot and was spoken of only as “milk”. Her main festival fell on the Kalends of May, when a celebration open to all Roman women was held in the temple and a sow (called the Damium) was sacrificed in honor of the goddess. The second ceremony to honor Bona Dea was held in December (the date was not fixed) and did not take place in the temple, instead being held in the house of the senior magistrate in Rome. Unlike the festival in May, it was privately funded and by invitation only. It was conducted by the wife of the magistrate with assistance by the temple’s vestal virgins.
Little is known about the particulars involved in the worship of this goddess. The details that are known all come from a relatively late source: Macrobius, a fifth century writer and philosopher. We do know that in 62 BCE the December celebration was held in the home of Julius Caesar, then praetor and Pontifex Maximus. His wife and mother were in charge. A politician named Publius Clodius dressed in women’s clothing and snuck into the house. Though Caesar’s mother caught him and sent him away, Caesar nevertheless divorced his wife, suspecting her of some treachery. Clodius was put on trial and Cicero blew his alibi, making the two mortal enemies. After these events, the December ceremony to honor Bona Dea fell into disrepute and was claimed by some to be no more than an orgy for women.
It is noteworthy that Angitia, a goddess of the Marsii, seems to be the same deity, and that Bona Dea has been identified with Cybele, Maia, Ge, Ops, Semele and Hecate.
Sources:
http://www.bates.edu/~mimber/Rciv/bonadea.htm
http://www.pantheon.org/areas/mythology/europe/roman/articles.html
http://www.virtualsolarsystem.com/members/mariamarius/