Mystères d'Éleusis
The Eleusinian Mysteries, (Greek: ) were annual initiation ceremonies in the cults of the goddesses Demeter and Persephone, held in secret at Eleusis (near Athens) in ancient Greece. The mysteries began in about 1600 B.C. in the Mycenean period and continued for two thousand years, becoming a major festival during the Hellenic era, and later spreading to Rome. Numerous scholars have proposed that the power of the Eleusinian Mysteries came from the kykeon's functioning as an entheogen.