Final Answer:
Persephone must spend one-third of the year, or four months, in Hades' realm according to the Homeric Hymn to Demeter.
Step-by-step explanation:
In the Homeric Hymn to Demeter, it's stated that Persephone spends a portion of the year in the underworld because she consumed pomegranate seeds while there. As a consequence, she must remain in Hades' realm for a fraction of the year. The hymn mentions that Persephone spends two-thirds of the year with her mother, Demeter, and one-third of the year in the underworld. As the year consists of twelve months, one-third of that amounts to four months, which Persephone must spend in Hades' realm annually. This cyclic pattern symbolizes the changing seasons, with her time in the underworld coinciding with winter and her return signifying the arrival of spring.
The hymn signifies the narrative behind the cycle of seasons, explaining the reason for winter and the return of life in spring. Persephone's time in the underworld, resulting from eating the pomegranate seeds, represents the dormant period in nature when growth and life seem to pause. This duration corresponds to the colder months when the earth appears barren.
Conversely, her return to the surface marks the rejuvenation of nature, as Demeter, her mother, rejoices, bringing forth the season of growth and vitality once again. This mythological explanation has been interpreted as an allegory for the cycle of life, death, and rebirth that is reflected in the changing seasons. Thus, the Homeric Hymn to Demeter provides an understanding of Persephone's annual sojourn in Hades' realm, which holds significance in the mythological representation of the changing natural world.