The Anthesteria was one of the four festivals in honour of Dionysus. It was celebrated at full moon at the beginning of spring. Wine pithoi stored at the previous vintage, were now ceremoniously opened. During the feast, social order was interrupted or inverted.. The Keres, ‘dark beings with gnashing teeth and claws and with a thirst for human blood’, were entertained, freely roaming the city until they were expelled after the festival. Compare excess, wine, and inversion of order with Purim.