Eleusinian Mysteries (ĕlyōsĭnˈēən) [key], principal religious mysteries of ancient Greece. The mysteries may have originated as part of an early agrarian festival peculiar to certain families in Eleusis. The Athenians later (c.600 B.C.) took over the ceremonies. Because the mysteries were secret, little is known of them. Presumably fasting and ritual purification in the sea took place before the large procession from Athens to Eleusis. The rites, which fundamentally celebrated the abduction and return of Persephone, symbolized the annual cycle of death and rebirth in nature as well as the immortality of the soul. It was believed that they had originally been instituted in Eleusis by Persephone's mother, Demeter. Dionysus was also much honored. The festival at Eleusis, known as the Greater Mysteries, was celebrated in the early fall, at sowing time. Another festival, the Lesser Mysteries, was held in the early spring at Agrae.
See G. E. Myloras, Eleusis and the Eleusinian Mysteries (1962, repr. 1969).