Tethys was the Titaness who married Oceanus and became the mother of the river gods.
Tethys was one of the twelve Titans born to Uranus, the sky, and Gaia, the earth. She married her brother Oceanus, whose cosmic river was believed to flow around the world. Together they formed an important mythological pair representing the generative and nourishing powers of primordial water.
According to Hesiod, Tethys and Oceanus had three thousand river-god sons and three thousand Oceanid daughters. Their descendants included Achelous, Alpheus, Scamander, Styx, Metis, Doris, and Eurynome. These figures connected the divine family to rivers, springs, nymphs, and the circulation of water throughout the mythic world.
Tethys plays little active role in surviving Greek myths, though Homer describes her and Oceanus as foster parents of Hera. She is frequently confused with Thetis, the sea nymph who married Peleus and was the mother of Achilles. Tethys later became associated poetically with the sea, and her name was also given to Saturn’s moon and the prehistoric Tethys Ocean.