Tethys was a Titaness, daughter of Uranus and Gaia, and the wife and sister of Oceanus, with whom Hesiod's Theogony credits her as the mother of three thousand river gods and three thousand Oceanid nymphs, one of the largest single families claimed for any pairing of Greek deities. Beyond this genealogical role, Tethys appears in only a handful of surviving stories. The most notable comes from Homer's Iliad, where Hera reminds Zeus that Oceanus and Tethys raised and cared for her as a foster child during the war between the Titans and the Olympians, sheltering her while Zeus deposed Cronus, a passage that gives Tethys a rare moment of independent character as a nurturing, protective figure rather than simply a name in a genealogy. Later mythographers add little to this picture. She does not fight in the Titanomachy, is not punished alongside the Titans who did resist Zeus, and retains, in most tellings, an association with fresh and salt water together, complementing rather than rivaling her husband's identity as the great encircling world river. Among her few individually named daughters are Styx, goddess of the river that bound the gods' own oaths, and Doris, mother of the fifty Nereids by the sea god Nereus, so that Tethys stands, through her children and grandchildren, at the root of an enormous share of Greek water mythology even though she herself remains a comparatively distant, background figure in almost every telling.