The building to the south of the Agora has been identified with the sanctuary of Demeter, mentioned by Pausanias during his tour of the city. Within the sanctuary, a cult building was discovered, dating to the 4th/ 3rd century BC, which was surrounded by auxiliary rooms. Beneath their floors a large number of terracotta votive plaques were found dating from the 7th to the 3rd century BC. They depict funerary banquets, horse riders, hoplites, standing and seated female figures and a group of three female figures.

The sanctuary was originally dedicated to the worship of a hero, but was later dedicated to Demeter. It probably housed the statues of the Dioskouroi, depicting them kidnapping the daughters of Leukippos.