Tethys (Greek Τηθύς ) was a titan and sea goddess in Greek mythology. The daughter of Uranus and Gaia was married to her brother Okeanos. One of her granddaughters was Thetis, from the mortal Peleus to Achilles gave birth later.
Tethys was a goddess of earthly sources of fresh water and the mother of Potamoi (rivers, like the Nile, the Alpheus and large meander ), around 3000 Oceanids ( springs, streams and wells ) and the Nephelai ( clouds). In the mythological idea Tehtys nurtured their children by providing them these through subsurface groundwater lines with the waters of Okeanus. Your name probably derives from the ancient Greek word Tethe from what grandmother does. On Greek vases Tethys is often next to Eileithyia, the goddess of birth, or her husband Okeanus to see. In some mosaics she wears a small pair of wings on the front. In poetry, it was later often depicted as the personification of the sea and partially equated with the sea goddess Thalassa.
During the war against the Titans Tethys Hera drew on that Rhea had entrusted to her. Homer described for example in the Iliad book 14 of them as Hera said to Aphrodite: " [ ... ] Now that I go to the ends of the earth to visit Okeanos [ ... ] and Tethys our mother who brought me kindly in their own house and has looked after me and took me by Rhea to be, at that time, as Zeus banished Cronus under the earth's surface and the barren water. [ ... ]. "
Hera was not pleased with the placement of Callisto and Arcas as constellations of the Great and Little Bear in the sky, so she asked her nurse Tethys for help. Tethys cursed the constellations forever to wander around the sky and never drop below the horizon.