She was the goddess of the Sea. She was one of the primordial gods born at the dawn of creation.
Parents: Aether and Hemera
With Pontus, she produced the fish and other sea creatures. Thalassa was the literal body of the sea and manifested as a woman formed of sea-water rising from her native element. Pontus and her were replaced by younger marine pairs; Oceanus and Tethys, then, Poseidon and Amphitrite.