The Eleusinian Mysteries () were a series of initiations held every year in honor of the Greek goddesses Demeter and Persephone. Based at the city of Eleusis (from which the name "Eleusinian" is derived), they are the "most famous of the secret religious rites of Ancient Greece." Scholars have proposed that the power of the Eleusinian Mysteries came also from drinking a psychedelic potion called "kykeon".