Many, but not all, of the deities worshiped in the mysteries were originally associated with fertility. As such, their associated myths often referred to the natural cycle as it waxes and wanes (for instance, Demeter) or to the dying and rising of a god (Attis, Adonis, Osirs). Some scholars thing that the mysteries used this feature of the myth to give symbolic expression of rising to immorality with the deity. However, not all scholars agree; some deities venerated in mystery religions did not die or rise; moreover, the exact use of the myth in the mysteries is often unclear, though some concept of immorality seems to be implied.
Public festivals were given in honor of some deities worshiped in the mystery religions, but their relationship to the secret rites is not clear. The spring festival of Cybele (March 15-27) involved processions, sacrifices, music, and frenzied dancing that led to castration. The public revelry, pantonmimes, theatric productions, and excesses of drink associated with the worshipers of Dionysisus/Bacchus (the Bacchanalia) are well known.
Rites of initiation into the mystery religions included ritual cleansing in the sea, baptism, and sacrifices. Mention should be made of the Tauroblium, used in the worship of Cybele, a rite in which a bull was slaughtered on a grill placed over a pit in which a priest stood; the person below eagerly covered himself with blood. Some have interpreted this as a rite of initiation, but it is more likely a purification ritual affording rebirth for a period of time, perhaps 20 years. The mystery religions dislodged religion from the traditional foundations of state and family and made it a matter of personal choice. With a few exceptions-for instance, Mithraism that was restricted to males-the mysteries were open to all classes and sexes. Those initiated formed an association bound together by secret rites and symbols peculiar to their cult. These associations met regularly with a designated leader in houses or specially built structures. The worshipers of Mithras met in a structure called a Mithraeum designed to imitate the cave in which Mithras killed the bull, the central act of the cult myth. Scenes of the slaying (tauroctony) appear prominently in several such structures.
At the meeting ritual acts or sacraments practiced by the particular cult were shared by the members. Mention is made of common meals or banquets. Members of the association were required to meet certain moral standards; some mention also is made of ascetic requirements. However, a word of caution is in order: generalizations about the mystery religions are difficult since each cult was individualistic. Exceptions to nearly all generalizations can be found.