Oceanus was the son of Uranus and Gæa.
He was the personification of the ever-flowing stream, which, according to the primitive notions of the early Greeks, encircled the world, and from which sprang all the rivers and streams that watered the earth.
He was married to Tethys, one of the Titans, and was the father of a numerous progeny called the Oceanides, who are said to have been three thousand in number. He alone, of all the Titans, refrained from taking part against Zeus in the Titanomachia, and was, on that account, the only one of the primeval divinities permitted to retain his dominion under the new dynasty.
From: Berens, E.M. The Myths and Legends of Ancient Greece and Rome. New York: Maynard, Merril, & Co., 1880. Text in the public domain.