Rhea (Greek: Ῥέα) is one of the Titans in Greek mythology. She is a daughter of Gaia and Ouranos. She was the sister and wife of Kronos. She was the mother of Hestia, Demeter, Hera, Hades, Poseidon, and Zeus). She was known as the "Great Mother" (Magna Mater). Rhea was not very important in the Ancient Greek religion. The Roman Rhea is Ops.