As Walter Burkert has shown definitively, mystery cults appeared in Greece as early as the sixth century BCE, if not earlier, and shared many common characteristics that make it difficult to distinguish clearly among them. Their interaction influenced both their discourse and practical matters. Without discrimination regarding religious convictions, gender, age, social or economic status, or nationality (only those who committed murder were discriminated against), initiation was open and tolerant. The mystes could decide at will to be initiated into as many mysteries as s/he wished to, in the hope of personally receiving rewards in this life or after death. In many mysteries, secrecy was enforced and revelation of the arrheta and aporrheta was severely punished. As it turns out, the oral and apparently written teachings concentrated on a hieros logos and involved both legomena and dromena, but evidence for the procedure is scanty or totally absent, except for one thing which was allowed to be revealed: the impact the mysteries had on the initiates (hence the allusions in literary texts). Through initiation, the mystes acquired a special relationship with the divine, what Burkert calls “the extraordinary experience.” This experience transformed her/his views on matters of life and death, as is shown by the epithets ὄλβιος, εὐδαίμων, μάκαρ, and ὅσιος employed for mystai, epithets otherwise reserved only for gods and heroes.
Cretan Epistomia in Context.)