Like the Eleusinian mysteries, the mysteries of the “Great Gods” (Theoi Megaloi) of Samothrace (a mountainous island in the northern Aegean) were highly respected in the ancient Mediterranean, particularly in the Hellenistic and Roman periods. Our evidence for the Samothracian gods and their mysteries is both literary and archeological.
Very little is actually known about the identity of these Great Gods, and there is a fair bit of uncertainty surrounding them both in ancient authors and in modern scholarly debates. One particular ancient commentator, named Mnaseas, seems to preserve their (non-Greek) names as expressed locally in Samothrace: Axieros, Axiokersa, Axiokersos, and Kasmilos (or Kadmilos). It is uncertain how many were male deities and how many female. A further difficulty is that many other Greek and Roman authors who refer to these gods identify them with non-Samothracian deities, including, most commonly, Demeter, Persephone, Hades, and Hermes, but also the Dioskouroi (Dioscuri), Kabeiroi (or Cabiri) and Korybantes. What does seem clear from our evidence is that there was at least one main female deity, along the lines of a “Great Mother” (who is depicted on some Samothracian coins), two other male deities that were depicted in statues with the phallus erect, and a fourth attendant figure (Kasmilos).
Writing in the first century, Diodorus of Sicily tells several stories associated with Samothrace, including the story of a flood and the foundation of the sanctuary and the wedding of Kadmos and Harmonia. But it is difficult to sort out how the figures in these stories relate to the four gods listed (above) by Mnaseas. Diodorus Siculus does indicate something of the significance of these mysteries, however:
Now the details of the initiatory rite are guarded among the matters not to be divulged and are communicated to the initiates alone; but the fame has traveled wide of how these gods appear to mankind and bring unexpected aid to those initiates of theirs who call upon them in the midst of perils. The claim is also made that men who have taken part in the mysteries become more pious and more just and better in every respect than they were before.
The Great Gods were especially known for protecting those who traveled by sea, so it is not surprising to find a room devoted to the Samothracian deities within the building constructed by the guild of fishermen and fish-dealers at Ephesos. Those who made the journey to Samothrace for the mysteries sometimes joined together with fellow initiates upon returning to their home-towns. There were unofficial associations devoted to the Great Gods at various locales in the Hellenistic and Roman eras, including the association (koinon) of Samothraciasts on the island of Rhodes, which are attested in several inscriptions.
This brings us to the actual mysteries of Samothrace themselves, which were open to men and women, slave and free, and were even more inclusive than the Eleusinian mysteries (which limited initiation to Greek-speakers). People traveled to the sanctuary for a yearly festival (the date of the festival is unknown) or for initiation from various parts of the Mediterranean, particularly from the regions of Thrace, Asia Minor, Macedonia, and Greece. Legend has it that Philip of Macedon, Alexander the Great's father, was initiated and spent considerable time at Samothrace.
The practices associated with the mysteries can be understood in relation to the excavations of the sanctuary (which took place primarily after WW I). As in the mysteries at Eleusis, there were two important stages in the mysteries of the Great Gods: the first stage of “initiation” (myesis), after which participants were considered “initiates” (mystai), and the second stage of “viewing” (epopteia), which was restricted to those who were already initiates. Unlike the mysteries of Demeter at Eleusis, however, it seems that a one-year wait was not necessary between the two stages, and initiation at either stage could also take place at various times in the year at Samothrace (not just during the official festival, as at Eleusis).
One of the main excavators, Karl Lehmann (1975), identifies two key buildings within the larger sanctuary that correspond to these two stages of the mysteries. The building labeled the “Anaktoron” (dating to the Roman period) was the most likely location of the first stage of initiation. This was a large hall (27m x 11.58 m) with wooden benches to seat the participants. Torches and lamps likely added further mystery to the night-time ceremony. Although the details are obscure, it seems that initiation involved ritual dances in the main hall followed by the showing of the sacred symbols in a smaller room accessible by two doors at the north end. These two doors may have been flanked by two ithyphallic statues (of the male Great Gods), mentioned earlier. An inscription found in this part of the building forbids entrance into this section to any that have not achieved “initiation” (myesis) in the main hall. Initiates who participated in the many other secretive and memorable rites likely received a purple belt and an iron ring to symbolize the experience and the protection which it ensured.
We know less about the second main stage (“viewing”) which most likely took place in the larger building (40m x 13m) identified as the “Hieron” (which dates to about 325 BCE). An inscription found near the building indicates that only those who had achieved the first stage of initiation could enter. It seems that a preliminary purification preceded entrance into the hall, where sacrifices were followed by ceremonies, including the revelation of sacred objects. Though the details of the Samothracian mysteries are obscure to us, what is clear is the high value that many participants attached to this experience. So much so that initiates continued to identify themselves as such (even forming associations) and continued to receive protection from the Great Gods long after returning to their home-towns.