A daughter of Gaia and Uranus, Rhea is one of the twelve Titans. After being freed from Uranus, she married her brother Cronus.
Cronus, knowing it was fated that he would be overthrown by his children, swallowed each child after Rhea gave birth. With the help of her mother Gaia, Rhea managed to save her last son, Zeus. She took him to a cave in Crete, and instead handed a stone to Cronus, which he immediately swallowed without first inspecting it.
Rhea was often identified with Cybele, whose cult spread throughout the ancient Mediterranean world. The Romans often identified Rhea with Ops, the goddess of abundance. This is most likely because Ops was usually associated with Saturn, who was, in turn, associated with Cronus.
Burkert, Walter. Ancient Mystery Cults. Harvard Press, 1987.