Titans
Rheia
In Greek mythology, Rheia is a Titaness, the daughter of Earth (Gaia) and Heaven (Uranos). According to Homer, she is represented as the mother of the gods. Her siblings were the Titans Okeanos, Koios, Krios, Hyperion, Íapetos, Kronos and the Titans Phoibe, Theia and Téthys.
Her husband, and brother, was Kronos, who married her after he overthrew Uranus. Their children were named Hestia, Demeter, Hera, Hades and Poseidon. But all of them were eventually swallowed by Kronos for fear that history would repeat itself and that his own children would deprive him of his rule in the future.
The youngest son (Zeus) escaped Kronos' threat through Rhea's cunning. For before Zeus was born, Rhea went to the island of Crete, where she gave birth in secret. She then gave Kronos a stone wrapped in swaddling clothes instead of the newborn. According to some legends, the same thing happened to Poseidon.
When Zeus came of age, he wanted revenge, so he mixed a honey drink with a poison and gave it to Cronus. Then Kronos overthrew all of Zeus' brothers and sisters, and the siblings teamed up to fight. Zeus freed the Hekatoncheires, won the Cyclopes and some of the Titans to his side, and after a decade of hard fighting, overcame Kronos and cast him into Tartarus.
Rhea was not held in any special esteem by the Greeks, even though she was the mother of the chief god.