Helios, in Greek religion, the sun god, sometimes called a Titan. He drove a chariot daily from east to west across the sky and sailed around the northerly stream of Ocean each night in a huge cup.
In classical Greece, Helios was especially worshipped in Rhodes, where from at least the early 5th century bce he was regarded as the chief god, to whom the island belonged. His worship spread as he became increasingly identified with other deities, often under Eastern influence. From the 5th century bce, Apollo, originally a deity of radiant purity, was more and more interpreted as a sun god. Under the Roman Empire the sun itself came to be worshipped as the Unconquered Sun.