Bona Dea is a Roman goddess, but it is highly probable that the Greek cult of Damia was grafted onto the original cult of the Roman goddess Bona Dea.
Bona Dea – the Good Goddess - is a divinity in ancient Roman religion. She is associated with chastity and fertility in Roman women, healing, and the protection of the state and people of Rome. According to Roman literary sources, she was brought from Magna Graecia at some time during the early or middle Republic, and was given her own state cult on the Aventine Hill, one of the Seven Hills on which ancient Rome was built.
The Aventine was a significant site in Roman mythology. In Rome's founding myth, the divinely fathered twins Romulus and Remus hold a contest of augury, whose outcome determines the right to found, name and lead a new city, and to determine its site. In most versions of the story, Remus sets up his augural tent on the Aventine; Romulus sets his up on the Palatine.
Bona Dea's rites allowed women the use of strong wine and blood-sacrifice, things otherwise forbidden them by Roman tradition. Men were barred from her mysteries and the possession of her true name. Given that male authors had limited knowledge of her rites and attributes, ancient speculations about her identity abound, among them that she was an aspect of Terra, Ops, Cybele, or Ceres, or a Latin form of the Greek goddess Damia - Demeter. Most often, she was identified as the wife, sister, or daughter of the god Faunus, thus an equivalent or aspect of the nature-goddess Fauna - said to be Bona Dea's secret name - who could prophesy the fates of women. Bona Dea's cults in the city of Rome were led by the Vestal Virgins, and her provincial cults by virgin or matron priestesses.
As the Roman Goddess of Women, she is often depicted as sitting on a throne holding a cornucopia with a snake next to her. The cornucopia represents plenty and abundance. Since Bona Dea’s themes are femininity, blessing, fertility, divination and abundance, Her symbols are vines and wine. So Bona Dea is a women’s Goddess who received offerings of wine in exchange for prophetic insights during Her observances.
Some online resources for understanding Bona Dea: