 This left a long period of time when Demeter was unhappy due to Persephone's absence, neglecting to cultivate the earth.When Persephone returned to the surface, Demeter became joyful and cared for the earth again.In the central foundation document of the mystery, the Homeric "Hymn to Demeter" line 415, Persephone is said to stay in Hades during winter and return in the spring of the year