This vessel was likely used as part of the Greek symposium. Much like modern academic symposiums, in which people discuss a topic of common interest, debunking old theories and putting forth new hypotheses; the men of ancient Athens regularly got together in private homes to exchange ideas. Afterward the participants might continue the conversation, discussing their impressions in greater detail or simply socializing over a drink. As the evening progressed, participants engaged in other pleasures, including games, performances, and sex.
Wine played a major role in fueling these evenings, and a myriad of vessels were used for preparing wine while smaller vessels like this one were used to serve and drink it. it would have been almost impossible to drink from this particular example and it was likely used instead as a mixing bowl (krater).
