The Titans were the twelve children of Ouranos and Gaea. The Titans (and Titanesses as the six daughters were sometimes known) Iapetus, Hypherion, Oceanus, Coeus, Creus, Theia, Rhea, Mnemosyne, Phoebe, Tethys, Themis and Kronos. Prometheus, Atlas, Hecate, Selene, and Helios — some of their descendants, were also often known as Titans.
Kronos was the youngest of the Titans, but he led the group to rebel against their father, Ouranos. Ouranos’ defeate gave the Titans rule over the universe. This rule lasted until Zeus, the youngest of Kronos’ offspring led his generation, The Olympic gods, to overthrow the Titans in a battle known as the “Titanomachy”. During this battle, Zeus freed the Cyclopes and the giant Hecatoncheires from Tartarus. The Cyclopes, who were smiths, fashioned Zeus’ thunderbolts, Hades’ helmet and Poseidon’s trident as a sign of their gratitude. These weapons were used to defeat the Titans.
After the battle, most of the Titans were condemmed to Tartarus. Prometheus, who had sided with Zeus, was allowed to remain with the new ruling gods. Atlas was condemed to carry the sky on his shoulders.