HESIOD'S THEOGONY, PGS. 74 AND 86

Kronos rapes Rheia who gives birth of Demeter, Hestia, Hera, and Hades. Kronos immediately swallows his children in fear that one day they will overthrow him. Rheia however, devises a way to hide their youngest son, Zeus, who later forces his father Kronos to throw up the other children. Later Zeus and Demeter slept together and Proseprine was the outcome of this union.