Diocles (or Dioclus) was one of the first priests of Demeter. According to the Homeric Hymn to Demeter, Eleusis was under the control of certain men, kings, and administrators, who had received their authority from the gods and enjoyed great respect from the people. Kallidike, the daughter of King Celeus, identifies them as Diocles, Triptolemus, Polyxenos, Eumolpos, Dolikhos, and Celeus. Diocles is called “driver of horses” and a “leader of the people”. When Persephone came back from the Underworld and the two goddesses prepared to return to Mount Olympus, Demeter decided to express her gratitude to the people of Eleusis for their hospitality in her time of need. So she gathered the kings mentioned above and taught them “the way to perform the sacred rites, and she pointed out the ritual to all of them”. According to Megarian tradition, Diocles was the Megarian ruler of Eleusis, who lost power after an intervention by Theseus, the legendary hero of Athens.