There are twelve Titans from their first literary appearance, in Hesiod, Theogony; Pseudo-Apollodorus, in Bibliotheke, adds a thirteenth Titan Dione, a double of Theia. The six male Titans are known as the Titanes, and the females as the Titanides ("Titanesses"). The Titans were associated with various primal concepts, some of which are simply extrapolated from their names: ocean and fruitful earth, sun and moon, memory and natural law. The twelve first-generation Titans were ruled by the youngest, Kronos, who overthrew their father, Oranos ('Sky'), at the urgings of their mother, Gaia ('Earth').
The Titans later gave birth to other Titans, notably the children of Hyperion (Helios, Eos, and Selene), the daughters of Coeus (Leto and Asteria), and the sons of Iapetus — Prometheus, Epimetheus, Atlas, and Menoetius; all of these descendants in the second generation are also known as "Titans".
The Titans preceded the Twelve Olympians, who, led by Zeus, eventually overthrew them in the Titanomachy ('War of the Titans'). The Titans were then imprisoned in Tartarus, the deepest part of the underworld, with the few exceptions being those who didn't fight with Kronos.
Uranus kept all of Gaia's children trapped within her womb, and Gaia groaned from the strain. Eventually, Cronus, her youngest child at the time, volunteered to set upon his father, castrating him, thereby freeing Gaia's children and setting himself up as king of the titans with Rhea as his wife and queen.
Rhea gave birth to a new generation of gods to Cronus, but, in fear that they too would eventually overthrow him, he swallowed them all whole one by one. Only Zeus was saved: Rhea gave Cronus a stone in swaddling clothes in his place, and placed the infant Zeus in Crete to be guarded by the Kouretes.
Once Zeus reached adulthood, he subdued Cronus by wile rather than force, using a potion concocted with the help of Gaia, his grandmother, to force Cronus to vomit up Zeus's siblings. A war between younger and older gods commenced, in which Zeus was aided by the Hecatonchires and Cyclopes, who had once again been freed from Tartarus. Zeus won after a long struggle, and cast many of the Titans down into Tartarus.
And yet the older gods left their mark on the world: Oceanus continued to encircle the world, and the name of "bright shining" Phoebe was attached as an epithet to effulgent Apollo, "Phoebus Apollo". Some of the Titans had not fought the Olympians and became key players in the new administration: Mnemosyne as a Muse, Rhea, Hyperion, Themis, or the "right ordering" of things and Metis.poems about the war between the gods and many of the Titans, the Titanomachy ("War of the Titans"). The dominant one, and the only one that has survived, was in the Theogony attributed to Hesiod. A lost epic Titanomachy attributed to the blind Thracian bard Thamyris, himself a legendary figure, was mentioned in passing in an essay On Music that was once attributed to Plutarch. And the Titans played a prominent role in the poems attributed to Orpheus. Although only scraps of the Orphic narratives survive, they show interesting differences with the Hesiodic tradition.
These Greek myths of the Titanomachy fall into a class of similar myths of a War in Heaven throughout Europe and the Near East, where one generation or group of gods by and large opposes the dominant one. Sometimes the Elder Gods are supplanted. Sometimes the rebels lose, and are either cast out of power entirely or incorporated into the pantheon. Other examples might include the wars of the Æsir with the Vanir and Jotuns in Scandinavian mythology, the Babylonian epic Enuma Elish, the Hittite "Kingship in Heaven" narrative, and the obscure generational conflict in Ugaritic fragments. The rebellion of Lucifer from Christianity could also fall under this category.
In one Orphic text, Zeus does not simply set upon his father violently. Instead, Rhea spreads out a banquet for Kronos, so that he becomes drunk upon fermented honey. Rather than being consigned to Tartarus, Kronos is dragged — still drunk — to the cave of Nyx (Night), where he continues to dream and prophesy throughout eternity.
Another myth concerning the Titans that is not in Hesiod revolves around Dionysus. At some point in his reign, Zeus decides to give up the throne in favor of the infant Dionysus, who like the infant Zeus is guarded by the Kouretes. The Titans decide to slay the child and claim the throne for themselves; they paint their faces white with gypsum, distract Dionysus with toys, then dismember him and boil and roast his limbs. Zeus, enraged, slays the Titans with his thunderbolt; Athena preserves the heart in a gypsum doll, out of which a new Dionysus is made. This story is told by the poets Callimachus and Nonnus, who call this Dionysus "Zagreus", and also in a number of Orphic texts, which do not.
One iteration of this story, reported by the Neoplatonist philosopher Olympiodorus, writing in the Christian era, says that humanity sprung up out of the fatty smoke of the burning Titan corpses. Other earlier writers imply that humanity was born out of the blood shed by the Titans in their war against Zeus.
She also points out that the word "Titan" comes from the Greek τιτανος, meaning white earth, clay or gypsum, and that the Titans were "white clay men", or men covered by white clay or gypsum dust in their rituals.
The scholar M.L. West also points this out in relation to shamanistic initiatory rites of early Greek religious practices. The element titanium is named for the titans.