Iapetus was one of the elder Titans and sons of Uranus and Gaia.
Parents: Uranus and Gaia
Siblings: Coeus, Crius, Cronus, Cyclops, Furies, Giants, Hecatoncheires, Hyperion, Oceanus, Meliae, Mnemosyne, Phoebe, Rhea, Tethys, Theia and Themis
Children: Anchiale, Atlas, Epimetheus, Menoetius and Prometheus
Led by Cronus, Iapetus and his brothers ambushed their father as he descended to lie with Gaia. Crius, Coeus, Hyperion and Iapetus were posted at the four corners of the world, where they seized hold of the their father and held him fast, while Cronus castrated him with a sickle. The Titans were later deposed by Zeus and cast into Tartarus.
Iapetus and his three brothers represent the four pillars of the cosmos. which are described in Near-Eastern cosmogonies holding heaven and earth apart. Iapetus himself would have been the pillar of the west, a position later held by his son Atlas.