mystery religion, Any of various secret cults of the Greco-Roman world. Derived from primitive tribal ceremonies, mystery religions reached their peak of popularity in Greece in the first three centuries ce. Their members met secretly to share meals and take part in dances and ceremonies, especially initiation rites. The cult of Demeter produced the most famous of the mystery religions, the Eleusinian Mysteries, as well as the Andania mysteries. Dionysus was worshipped in festivals that included wine, choral singing, sexual activity, and mime. The Orphic cult, by contrast, based on sacred writings attributed to Orpheus, required chastity and abstinence from meat and wine. Mystery cults also attached to Attis, Isis, and Jupiter Dolichenus, among others.