This article examines the context in which Caesar, enthroned in state, attended the Festival of the Lupercalia of 44 B.C. at which he was offered and rejected a diadem; it asks the question what the ritual had to offer to Caesar. An examination of the Festival's character and tradition suggests (a) that it took the form of a street carnival, (b) that it was concerned simultaneously with the purification, fertility and protection of the people of Rome, and (c) that it had no element of a coronation in its rituals. The suggestion is offered that Caesar's prime motivation was to associate himself with the founders of the city, since he and his family were receiving the honour of a new group of Luperci, set up to parallel those of Romulus and Remus. If Antony's offering of the diadem was pre-arranged, the light-hearted and provocative atmosphere of the occasion strongly suggests that the plan must always have been that Caesar should publicly reject the offer, as he did. But the whole incident illustrates the vigour and creativity of religious life at the time.