Rhea is the daughter of the gods , Uranus and Gaia . She is the mother of Demeter , Hades , Hera , Hestia , Poseidon , and Zeus . Cronus sired six children by Rhea : Hestia , Hades , Demeter , Poseidon , Hera and Zeus in that order , but swallowed them all as soon as they were born except Zeus , since he had learned from Gaia and Uranus that he was destined to be overcome by his own child as he had overthrown his own father .