The term 'Mother of the Titans' refers to two figures in Greek mythology: Gaea (also spelled Gaia) and her daughter, Rhea. Gaea was the primordial goddess of the Earth, and Rhea was the mother of the twelve Olympian gods. Gaea is often referred to as the 'Mother of All, ' while Rhea is known as the 'Mother of the Titans.' Both Gaea and Rhea were important figures in Greek mythology, and their stories are still told today.