The Olympians are the twelve principal gods of the Greeks, who were thought to live on Mount Olympus and who ruled the world under Zeus after the defeat of the Titans. They are Zeus, Hera, Poseidon, Demeter, Athena, Apollo, Artemis, Ares, Aphrodite, Hephaestus, Hermes and Hestia, with Dionysus sometimes counted in her place. The early sources do not give one fixed list of the twelve.
Homer speaks of the gods as living in houses on Olympus (Iliad 1.18). Hesiod traces the family. Zeus, Hera, Poseidon, Demeter and Hestia were children of the Titans Cronus and Rhea, and so was Hades (Hesiod, Theogony 453–458). Zeus then fathered many of the other gods. Leto bore him Apollo and Artemis, and Maia bore Hermes (Hesiod, Theogony 918–920, 938–939). Hera bore Ares, and Hephaestus was born to her without a father; Athena came out of the head of Zeus himself (Hesiod, Theogony 921–929). Aphrodite, in Hesiod, was born from the foam around the severed genitals of Uranus (Hesiod, Theogony 188–198). Dionysus was the son of Zeus and the mortal Semele, and Hesiod says that “now both are gods” (Hesiod, Theogony 940–942).
The Greeks had altars and paintings of the Twelve Gods. Thucydides says that the younger Pisistratus set up the altar of the Twelve Gods in the Athenian agora (Thucydides 6.54.6), and Pausanias saw a portico in Athens with paintings of the Twelve (Pausanias 1.3.3). None of these passages names the twelve. Plato counts Hestia among them: in the Phaedrus, Zeus leads the other gods in the sky, while Hestia alone stays in the house of the gods (Plato, Phaedrus 247a).
Hades is a brother of Zeus and Poseidon, but his share of the world is the realm below. Poseidon says in the Iliad that the three brothers divided the universe: Poseidon took the sea, Hades the gloom of the underworld, and Zeus the broad sky, while the earth and Olympus remained common to all (Iliad 15.187–193). Since his realm lies below the earth, Hades and his wife Persephone are not usually counted among the Olympians.
Hesiod says that Uranus was overthrown by his son Cronus (Hesiod, Theogony 154–182), who swallowed his children as they were born. Rhea hid the youngest, Zeus, and Cronus was made to give up the others (Hesiod, Theogony 453–506). The gods then fought the Titans in the Titanomachy. With the help of the hundred-handed giants the Olympians defeated the Titans and threw them down beneath the earth (Hesiod, Theogony 617–721). On the advice of Gaia, the gods then urged Zeus to be their king, and he distributed their honours among them (Hesiod, Theogony 881–885).
Homer, Iliad 1.18, 15.187–193; Hesiod, Theogony 154–198, 453–506, 617–721, 881–885, 918–942; Plato, Phaedrus 247a; Thucydides 6.54.6; Pausanias 1.3.3.
See Also: Zeus, Hera, Poseidon, Demeter, Athena, Apollo, Artemis, Hestia, Dionysus, Hades