Initiates arriving at the sanctuary

A mythological reference about Eleusinian mysteries has to do with Heracles .
Heracles was to battle with the sinister powers of the underworld, to bring out of Hades Cerberus, the watchdog of Hell. This monster had three dog-heads with gaping jaws always slobbering venom, his body ended in a dragon's tail, and the hairs on his heads and his back were writhing snakes.
To prepare himself for this terrible quest, Heracles went to the city of Eleusis in Attica, where wise priests headed a secret cult concerning divine matters both in the upper and in the underworld. In this holy place the priest Eumolpus initiated Heracles into mystic teachings, after he had first purified him of the murder of the centaurs. Thus girded with the knowledge of secret things and prepared to face the terrors of the lower world, he journeyed to the Peloponnesus, to the city of Taenarum in Laconia, where there was an entrance to Hades.

The cult of Demeter at Eleusis was belonged to the original inhabitants, as is suggested sufficiently clearly by its nature and confirmed by archaeological evidence. Excavation on the site has revealed a continuity of occupation from Mycenean times, and the telesterion, where the final rites were performed, was actually built over the ruins of the megaton of some Mycenean king. This reminds us of how Athena had her temple on the site of the palace of the prehistoric overlords of the Akropolis at Athens. The fact that in historical times the management of the cult was in the hands of a single family or clan, the Eumolpidai, may preserve the memory of an origin in the family rites of the local chief and his relations. The telesterion itself is a curious building, not a temple but a large rectangular assembly-hall with a stepped auditorium at one end, to which the nearest parallels are found in so-called "theatres" at Knossos and Phaistos in Crete. That the cult took its origin from Crete is extremely likely, and agrees with the opinion of the Greeks themselves. Describing the generations of the gods in the Theogony, Hesiod says that the birth of Plutos the god of wealth was the result of the union of Demeter with Iasion "in the rich land of Crete". In the Homeric Hymn to Demeter a rich store of purely Eleusinian mythology (for it dates from before the time when the little town came under the sway of Athens), Demeter, in grief for her daughter Persephone who has been snatched away by Hades, leaves the company of the gods and wanders over the earth in search of her.

The secret behind the Eleusinian ?

The cult at Eleusis has always been recognized, in ancient as in modern times, to have been an agricultural one. When Demeter in wrath and grief at the rape of Persephone  neglects her wonted occupation, the result is a cessation of the fruits of the earth.

Zeus has intervened, and persuaded Demeter to agree to the arrangement whereby Persephone is to spend a third of the year below the earth and two-thirds in the upper world with her mother.

The town of Eleusis lay in Attica, only about twelve miles by road from Athens, and this accident of situation changed its history. It was united with its greater neighbour, and so found its mysteries first taken under her protection, and later, owing to the predominance of Athenian culture in Greece, raised to a position of Pan-Hellenic importance. Athens gave full official status to the mysteries, which were put under the charge of the King-Archon and a body of overseers of whom two were chosen from each of the priestly Eleusinian clans of the Eumolpidai and Kerykes and two from the whole Athenian people. A branch sanctuary, the Eleusinion, was built close under the Akropolis, where sacrifices were offered to Pluto and at the beginning of the great mysteries certain "sacred objects" from Eleusis were deposited, to be carried out again in the procession a few days later. On the strength of her control of the Eleusinian mysteries, it was claimed that the two greatest gifts of the gods to man—the arts of agriculture which first made possible a civilized life on earth, and the promise of a better life after death—had been revealed by heaven solely to the Athenians, and only through their generosity imparted to the rest of mankind. The Greeks still lived close enough to agricultural pursuits, and to the memory of a time before they were known, to realize their far-reaching significance.

An inscription of later date (117 B.C.), of which one copy was set up in the Athenian treasury at Delphi and another on the Akropolis of Athens, records a decree of the Amphictyonic Council conferring certain privileges and exemptions on the Athenian guild of Dionysiac artists (i.e. actors). It uses language like this. The Athenian people "converted men from the life of beasts to civilization and contributed to their mutual association by being first to impart the mysteries, and by their means proclaiming to all that the greatest good among men is mutual commerce and good faith.

A new god, arose from the connexion of the mysteries with Athens. This was lacchos. To cover the distance from Athens to Eleusis a procession was formed and passed along what came to be known as the Sacred Way between the two towns with dancing, singing and joyful shouts. From this, by the personification which came so readily to the Greek mind, arose the idea of a god of the joyful cry, and who was he likely to be but Dionysos, himself the patron of wild dancing.

The cry was now regarded as an invocation to Iacchos, and Iacchos identified with Dionysos, with whose dress and attributes his image was adorned.
One of these preliminary rites was purification by bathing in the sea, for which all candidates for initiation went down to the coast close to Athens on an appointed day. The procession took more than one day to cover the twelve miles of road, for it had to halt for all sorts of performances by the way.

At a certain bridge across the river Kephissos, a curious practice was observed that must have far antedated the days of the procession and been incorporated in it. As the procession arrived, one of its number sitting on the bridge, and answered possibly by the others, hurled abuse and curses, as one authority says, "at the most distinguished of the citizens". This "bridgery" (gephyrismos), as the often obscene jesting and cursing came to be called from the scene of its enactment, was not confined to the Eleusinian procession nor to the Kephissos bridge.

The secret was well kept. Some writers, have claimed to know and to reveal it, but we may well be chary of accepting their late as evidence for what went on at Eleusis in the fifth or fourth century B.C. We know however that it consisted of a revelation or spectacle, even if there is doubt as to the precise nature of the things revealed. All evidence leads to the conclusion that the effect was achieved by immediate action upon the senses. The initiate was shown things, and convinced of his salvation by the evidence of his own eyes. The climax was called the beholding and the chief officiating priest the hierophant, which means literally a showman of holy things. He was not a teacher. As Aristotle said, the initiate was not required to learn anything, but rather after suitable preparation to undergo an experience and be put in a certain state. One can scarcely speak of anything so definite as doctrine in connection with Eleusis. The root idea was more akin to magic, whose efficacy depends on the thoroughness of the preparatory measures and the punctilious correctness with which certain prescribed actions are carried out. Clearly also a large part was played by the emotional state which had been induced by the series of preliminary actions leading to the ultimate revelation set, as it appears, in a scene of contrasts between darkness and the dazzling light of hundreds of torches.

It is likely to seem an over-refinement to the ordinary man of a later age who is longing for some hint of a promise that death is not the end of everything that matters. After the passing of the epic age the idea of Elysium is more likely to return to what, if its pre-Greek origin may be accepted, was probably its original function. So when the Athenians, and under their leadership the whole of Greece, took over Eleusis, they fused the old idea of immortality, connected with the cult of Demeter and Persephone, with Homer's teaching about Elysium.

Later writers speak of those initiated in certain mysteries as reborn. Some others speak about reincarnation. Some have held that the final ceremony at Eleusis actually contained a rite symbolically enacting the rebirth of the initiate from the womb of Demeter.