Demeter was the goddess of fertility. She protected the field and the corn and also looked  after flowers and fruits. Demeter had a daughter with Zeus, Persephone. They were strongly connected and often she gets mentioned in connection with Demeter. Her symbols were the narcissus, the poppy and the crane.

But somehow Hades, the god of the underworld, fell in love with Persephone and kidnapped her. Demeter mourned a long time and, as she knew from the sun god Helios that it was Hades who had taken away her daughter, she went on strike. Then she left the Olympus and disregard all her task. Soon the earth got infertile. She worked as a usual women for the King Keleus of Eleusis. Nothing bloomed, nothing grew and a lot of necessary things were missing.

At that point Zeus ordered to release Persephone from the underworld. However, she was still connected with the underworld through a pomegranate Hades gave her and had to spend half a year on the Olympus and the other half in the underworld.