He set up an " intelligence bureau " in Rome, instituted mysteries like those of Eleusis, from which his particular enemies the Christians and Epicureans were alike excluded as " profane," and celebrated a mystic marriage between himself and the moon.
The incident has been assigned to various other localities - Crete, Eleusis, and Enna in Sicily, the last being most generally adopted.
In the form of an old woman named Deo (= the " seeker," or simply a diminutive form), she comes to the house of Celeus at Eleusis, where she is hospitably received.
Demeter then returns to Olympus, but before her final departure from earth, in token of her gratitude, she instructs the rulers of Eleusis in the art of agriculture and in the solemnities and rites whereby she desires in future to be honoured.
At Eleusis, Demeter was venerated as the introducer of all the blessings which agriculture brings in its train - fixed dwelling-places, civil order, marriage and a peaceful life; hence her name Thesmophoros, " the bringer of law and order," and the festival Thesmophoria.