Myth establishes ties of mutual obligation between mankind and the gods, establishes cultural cohesion, and shapes the cycle of the year.

The social function of myth is to bind a society together, to act as a charter for its laws and customs, and to embed a culture in its environment. The ritual year is not an abstraction, but an armature on which our lives are sculpted. Even the days of our week recall gods we no longer recognize—Tiw’s day, Woden’s Day, Thunor’s Day, Frigg’s Day, Saturn’s Day—while our year is punctuated with rituals both religious—Easter, Christmas, Diwali, Eid—and secular, from Valentine’s day to Halloween.

There are cultures where the ritual requirements are so complex and time-consuming many years may be required for a complete cycle—among the Elema of Papua New Guinea, the hevehe ritual dance cycle, in which dancers in elaborate masks communicated with sea spirits, lasted between seven and twenty years. But most cultures have used the turning of the seasons as the armature of their religious life, and to talk about the ritual year seems natural to us .

Ovid’s long poem Fasti examines the myths, legends, and rites of the Roman year, though sadly he only wrote the first six books, from January to June.

         Fasti begins with a long dialogue with “Two-headed Janus, source of the silent-gliding year,” and proceeds day-by-day in wonderful detail. For instance 15 March (the Ides of March, the day on which Julius Caesar was assassinated, though Ovid tells us that it was only his shadow that was struck down, the man himself being whisked away to the court of Jupiter by the goddess Vesta) was the feast of Anna Perenna, eternal Anna, a goddess of the year who was worshipped in a sacred grove on the Via Flaminia. Ovid vividly describes the merrymaking that marked this feast day of the common people, the plebs, who sang, danced, and got drunk along the banks of the Tiber. Ovid tells three myths about Anna Perenna with great pleasure.

         In the first of these, Anna’s story links back to the very beginning of Rome, for she was originally the sister of Dido, the queen of Carthage who was the doomed lover of Aeneas. Fleeing after Dido’s suicide, Anna eventually came to Latium, where Aeneas recognised her and took her into his household. But the blood-stained ghost of Dido appeared to her in the night, warning her that Aeneas’s jealous wife Lavinia was planning to kill her. So Anna fled, only to be raped by the horned river god Numicius, who subsequently transformed her into a nymph, Anna Perenna, a kind of demi-goddess who aged in phase with the moon.

         Ovid’s two other myths both tell of Anna in her old age. In one, she is an old woman of Bovillae who cooked food for the plebs when they had fled to the top of the Sacred Mountain (Mons Sacer) and were in danger of starvation. This explains why the plebs would especially celebrate her festival, though it doesn’t really link up with the story about her being Dido’s sister. The other myth of Anna Perenna is a comic tale in which Mars, having fallen in love with Minerva, begs Anna for her help. She strings him along, and at last tells him that Minerva has agreed to be his. But when in the bedroom Mars lifts the bridal veil, it is Anna’s wrinkled old face he sees, not that of the goddess. It is because of this bawdy trick, Ovid tells us that “old jokes and obscene verses” are chanted at Anna’s feast.

         The Anna Perenna who fools the amorous Mars could be either Anna of Carthage or Anna of Bovillae, but Ovid throws out other options too—some say Anna is Luna, the moon, others that she is the Greek goddess Themis, others that she is Io, and yet others identify her with the nymph Azanis “who gave Jupiter his first food.” All of these mythic identities are equally valid to Ovid, and he doesn’t try to make us or the plebeian revellers by the Tiber choose between them. The important thing is that the feast has this mythic backdrop, not that one story should outweigh any other.

        Ronald Hutton's The Stations of the Sun: A History of the Ritual Year in Britain, is a kind of British version of Fasti, and a similar study could be made of any culture, revealing a complex web of inherited attitudes and beliefs, as expressed in rituals and customs.