In Greek mythology, Heracles completed twelve labors.
The labors were imposed after Heracles killed his wife and children during a madness sent by Hera. Seeking purification and guidance, he consulted the oracle at Delphi. The oracle directed him to serve Eurystheus, king of Tiryns and Mycenae, who assigned a series of tasks intended to be impossible.
The best-known labors include killing the Nemean Lion, defeating the nine-headed Lernaean Hydra, capturing the Erymanthian Boar, obtaining the Golden Apples of the Hesperides, and bringing Cerberus out of the Underworld. Heracles originally received ten tasks, but Eurystheus rejected two: the Hydra because Heracles had help, and the Augean stables because Heracles accepted payment.
That rejection increased the final total to twelve. Heracles is the Greek hero’s name; “Hercules” is its Roman form. Lists can differ in wording and order, but the canonical number of accepted labors is twelve.