Iapetus, in Greek mythology, son of Uranus and Gaea, one of the Titans, father of Atlas, Prometheus, Epimetheus and Menoetius, the personifications of certain human qualities (Hesiod, Theog. 507). As a punishment for having revolted against Zeus, he was imprisoned in Tartarus (Homer, Iliad, viii. 479) or underneath the island of Inarime off the coast of Campania (Silius Italicus xii. 148). Hyginus makes him the son of Tartarus and Gaea, and one of the giants. Iapetus was considered the original ancestor of the human race, as the father of Prometheus and grandfather of Deucalion. The name is probably identical with Japhet (Japheth), and the son of Noah in the Greek legend of the flood becomes the ancestor of (Noah) Deucalion. Iapetus as the representative of an obsolete order of things is described as warring against the new order under Zeus, and is naturally relegated to Tartarus.
See F. G. Welcker, Griechische Götterlehre, i. (1857); C. H. Völcker, Die Mythologie des Iapetischen Geschlechtes (1824); M. Mayer, Giganten und Titanen (1887).