Proserpina or Persephone is the Roman goddess of the underworld. Pluto, the god of the underworld, kidnapped Ceres's daughter, Proserpina, and took her to live with him. A single mother, Ceres felt abandoned by her daughter's absence. Proserpina ate six pomegranate seeds, an action that could have sealed her fate to live in the underworld forever. But Ceres, being a shrewd mother, was able to negotiate through Iuppiter with Pluto for her daughter's custody. Proserpina would spend half of the year with Pluto in the underworld and half of the year living with her mother. During the time Proserpina was in the underworld, Ceres was so grief-stricken that she refused to allow anything on Earth to be beautiful or fruitful, and these are the winter months. When Ceres has her daughter to look after, she is happy and the earth brought forth crops, giving food, so we have summer and the autumn harvest.
"The Trinacrian land took its name from its shape: It runs out in three rocky capes to the vast ocean. It’s a place dear to Ceres. She owns, there, many cities, Among them fertile Enna, with its well-ploughed soul. Cool Arethusa gathered together the mothers of the gods: And the yellow-haired goddess came to the sacred feast. Her daughter, Persephone, attended by girls, as ever, Wandered barefoot through Enna’s meadows. In a shadow-filled valley there’s a place, Wet by the copious spray from a high fall. All the colours of nature were displayed there, And the earth was bright with hues of various flowers. On seeing it she cried: ‘Come here to me, my friends, And each carry back, with me, a lapful of flowers.’ The foolish prize enticed their girlish spirits, And they were too busy to feel weary. Proserpine herself plucked fragile crocuses and white lilies. Intent on gathering them, she gradually strayed, And none of her friends chanced to follow their lady. Dis, her uncle saw her, and swiftly carried her off, And bore her on shadowy horses to his realm. She called out: `Oh, dearest Mother, I'm being Carried away!' and tore at the breast of her robe: Meanwhile a path opened for Dis, since his horses Can scarcely endure the unaccustomed daylight. When her crowd of friends had gathered their flowers, They shouted: `Persephone, come for your gifts!' But silence met their call: they filled the hills with their cries, And sadly beat their naked breasts with their hands. Ceres was startled by their grief (she'd just now come from Enna), And cried instantly `Ah me! Daughter, where are you?' She rushed about, distracted, as we've heard The Thracian Maenads run with flowing hair. As a cow bellows, when her calf's torn from her udder, And goes searching for her child, through the woods, So the goddess groaned freely, and ran quickly, As she made her way, Enna, from your plains. There she found marks of the girlish feet, and saw Where her familiar form had printed the ground: Perhaps her wandering would have ended that day, If wild pigs hadn't muddied the trail she found." - Ovid, Fasti IV
"Plouton fell in love with Persephone, and with Zeus' help secretly kidnapped her. Ceres roamed the earth over in search of her, by day and by night with torches. When she learned from the Hermionians that Plouton had kidnapped her, enraged at the gods she left the sky, and in the likeness of a woman made her way to Eleusis. She first sat upon the rock that has come to be called Agelasttos after her, beside the well called Kallikhoron. Then she went to the house of Keleus, the current ruler of the Eleusinians. After the woman inside invited her to sit with them, one old granny named Iambe joked with the goddess and got her to smile. For this reason they say that the women at the Thesmophoria joke and jest. Metaneira, the wife of Keleus, had a baby, which was given to Demeter to nurse. Wishing to make it immortal, she would set the baby in the fire at night and remove its mortal flesh. But because Demophon (the baby's name) grew so wondrously each day, Metaneira kept an eye on him, and when she spied him being buried in the fire she screamed. The child was thereupon destroyed by the fire, and the goddess revealed her true identity. When Zeus commanded Plouton to send Persephone back up, Plouton gave her a pomegranate seed to eat, as assurance that she would not remain long with her mother. With no foreknowledge of the outcome of her act, she consumed it. Askalaphos, the son of Akheron and Gorgyra, bore witness against her, in punishment for which Demeter pinned him down with a heavy rock in Hades' realm. But Persephone was obliged to spend a third of each year with Plouton, and the remainder of the year among the gods." - Apollodorus, The Library 1.29
"Pluto asked from Jove that he give him in marriage Ceres' daughter and his own. Jove said that Ceres would not permit her daughter to live in gloomy Tartarus, but bade him seize her as she was gathering flowers on Mount Etna, which is in Sicily. While Proserpina was gathering flowers with Venus, Diana, and Minerva, Pluto came in his four-horse chariot, and seized her. Afterwards Ceres obtained from Jove permission for her to stay half of the year with her, and half with Pluto." - Hyginus, Fabulae 146