It was a particular festival amongst Athenians, celebrated on the twelfth [day] of [the] month Anthesterion. But Apollodorus says that Anthesteria is the name for the festival as a whole, celebrated in honour of Dionysos, with its component parts Pithoigia ["Jar-Opening"], Choes ["Pitchers"], Chytroi ["Pots"].
And elsewhere [sc. Apollodorus says] that Orestes arrived in Athens after the murder (it was a festival of Dionysos Le[m]naios),[1] and since, having murdered his mother, he might not be able to drink with them, something along the following lines was contrived. Having set up pitchers of wine for each of the celebrants he ordered them to drink from it, with no common sharing between them; thus Orestes would neither drink from the same mixing-bowl [sc. as anyone else] nor be upset at him because he was made to drink alone. Hence the origin of the Athenian festival of the Pitchers.