Demeter was the daughter of Cronos and Rhea, and sister of Zeus. She was the goddess of cultivated land, of grain, crops, and fruit. As these things were needed to live, she was a very important goddess.

Demeter, Triptolemus and Persephone

Myths of Demeter

Demeter's daughter was Persephone. Persephone was kidnapped by Hades and taken to the underworld to be his wife. Demeter wandered sadly for nine days looking for her daughter. She rested at Eleusis, and revealed the secrets of growing grain to Triptolemus.

Because Demeter had left Olympus the earth became barren. Eventually Zeus made an arrangement for Persephone to spend half the year with her mother and half with Hades. This is how the Greeks explained the seasons, growth in Spring and summer and death in winter.