Driven mad by Hera, Hercules slew his own six sons. After recovering his sanity, Hercules deeply regretted his actions; he was purified by King Thespius, then travelled to Delphi to inquire how he could atone for his actions. The oracle Pythoness advised him to reside at Tyrins and serve King Eurystheus for twelve years, performing whatever labour might be set him; in return, he would be rewarded with immortality. Hercules despaired at this, loathing to serve a man whom he knew to be far inferior to himself, yet afraid to oppose his father Zeus. Eventually he placed himself at Eurystheus's disposal.
Eurystheus ordered Hercules to perform ten labours. Hercules accomplished these tasks, but Eurystheus refused to recognize two: the cleansing of the Augean stables, because Hercules was going to accept pay for the labour; and the killing of the Lernaean Hydra, as Hercules' nephew and charioteer Iolaus had helped him burn the stumps of the heads. Eurystheus set two more tasks (fetching the Golden Apples of Hesperides and capturing Cerberus), which Hercules performed successfully, bringing the total number of tasks to twelve.
- Skinning the Nemean Lion
- Killing the nine-headed hydra
- Capturing the hind of Ceryneia, the female pet deer of the Goddess Diana
- Capturing alive the Eyrmanthian boar
- Cleaning the stables of King Augeas
- Driving away the Stymphalian birds
- Wrestling the Cretan bull
- Capturing the man-eating horses of Diomedes
- Stealing the belt of Hippolyte, Queen of the Amazons
- Capturing the cattle of Geryon
- Stealing the golden apples of Hesperides, that belonged to Zeus
- Capturing Cerberus, the three-headed dog that guarded the entrance to Hades