DEMETER ~ THE GODDESS OF HARVEST

In the Greek Religion, Demeter ( Greek: Δημήτηρ) is the Goddess of the grain, agriculture, harvest, growth, and nourishment, who presides over grains and the fertility of the earth. 

Though Demeter is often described simply as the Goddess of the harvest, She also presides over the sacred law, and the cycle of life and death. She and Her daughter Persephone are the central figures of the Eleusinian Mysteries, a religious tradition that predated the Olympian pantheon, and which may have its roots in the Mycenaean period, c. 1400–1200 BCE.

In addition to her role as an agricultural Goddess, Demeter is often worshipped more generally as a Goddess of the earth. In Arcadia, She was represented as snake-haired, holding a dove and dolphin, perhaps to symbolize Her power over the underworld, the air, and the water.The Athenians called the dead "Demetrioi", and this may reflect a link between Demeter and an ancient cult of the dead, linked to the agrarian belief that a new life would sprout from the dead body, as a new plant arises from buried seed. This was probably a belief shared by initiates in Demeter's mysteries, as interpreted by Pindar: "Happy is he who has seen what exists under the earth, because he knows not only the end of life, but also his beginning that the Gods will give".

Demeter's epithets show Her many religious functions. She is the "Corn-Mother" who blesses the harvesters.
Potnia ("mistress") in the Homeric Hymn to Demeter. Hera especially, but also Artemis and Athena, are addressed as "Potnia" as well.
Despoina ("mistress of the house"). This title was also applied to Persephone, Aphrodite and Hecate.
Thesmophoros ("giver of customs" or even "legislator"), a role that links Her to the even more ancient goddess Themis, derived from thesmos, the unwritten law. 
Chloe ("the green shoot"), that invokes Her powers of ever-returning fertility, as does Chthonia.
Europa ("broad face or eyes"). 

Some of the earliest accounts of Demeter's relationships to other deities comes from Hesiod's Theogeny. In it, Demeter is described as a daughter of Cronos and Rhea.

Demeter's most well-known relationship is with Her daughter, Persephone, Goddess of the Underworld. Both Homer and Hesiod described Persephone as Zeus' daughter. Demeter and Persephone are often worshiped together and are often referred to by joint cultic titles. In their cult at Eleusis, they were referred to simply as "the Goddesses", often distinguished as "The Older" and "The Younger".

Demeter's daughter, Persephone, was abducted and taken to the Underworld by Hades. Demeter searched for Her ceaselessly, preoccupied with Her loss and Her grief. The seasons halted; living things ceased their growth, and began to die. Faced with the extinction of all life on earth, Zeus sent his messenger Hermes to the Underworld to bring Persephone back. Hades agreed to release Her if she had eaten nothing while in his realm; but Persephone had eaten a small number of pomegranate seeds. This bound her to Hades and the underworld for certain months of every year, either the dry Mediterranean summer, when plant life is threatened by drought, or the autumn and winter. There are several variations on the basic story. In the Homeric hymn to Demeter, Hecate assists in the search and later becomes Persephone's Underworld attendant. In the Homeric Hymn to Demeter, Persephone is secretly slipped a pomegranate seed by Hades. In another, Persephone willingly and secretly eats the pomegranate seeds, thinking to deceive Hades, but is discovered and made to stay. Contrary to popular perception, Persephone's time in the Underworld does not correspond with the unfruitful seasons of the ancient Greek calendar, nor her return to the upper world with springtime. Demeter's descent to retrieve Persephone from the underworld is connected to the Eleusinian Mysteries.

SOURCE: Wikipedia