Anna Perenna was an old Roman deity of the circle or "ring" of the year, as the name (per annum) clearly indicates. Her festival fell on the Ides of March (March 15), which would have marked the first full moon in the year in the old lunar Roman calendar when March was reckoned as the first month of the year, and was held at the grove of the goddess at the first milestone on the Via Flaminia. It was much frequented by the city plebs.
According to Macrobius, related that offerings were made to her ut annare perannareque commode liceat, i.e. "that the circle of the year may be completed happily" and that people sacrificed to her both publicly and privately. Johannes Lydus says that public sacrifice and prayers were offered to her to secure a healthy year. Ovid in his Fasti (3.523f) provides a vivid description of the revelry and licentiousness of her outdoor festival where tents were pitched or bowers built from branches, where lad lay beside lass, and people asked that Anna bestow as many more years to them as they could drink cups of wine at the festival.