In Greek mythology, twelve gods traditionally made up the main Olympian pantheon.
The Twelve Olympians were the principal gods associated with Mount Olympus. Common lists include Zeus, Hera, Poseidon, Demeter, Athena, Apollo, Artemis, Ares, Aphrodite, Hephaestus, Hermes, and either Hestia or Dionysus. Lists vary because Hestia was sometimes said to give her place to Dionysus.
The number twelve was traditional rather than a perfectly fixed membership rule. Hades was an important brother of Zeus, but he usually was not counted among the Twelve because he ruled the underworld rather than living on Olympus. Some local traditions also treated other deities differently.
The Olympians were connected through family relationships, marriages, rivalries, and shared myths. Their stories became central to ancient Greek religion, literature, sculpture, and later European art.