Although far inferior to Heracles in courage and might Eurystheus had cunning, and he devised a series of tasks that were next to impossible to complete. These were the "Twelve Labors of Heracles" that the hero undertook in his twelve years of servitude to the spiteful king.
His first labor was to kill the Nemean lion, an animal with an impenetrable hide. After vainly attacking it with arrows Heracles finally throttled the beast with his bare hands and carried it back to Mycenae. Eurystheus then resolved that Heracles must remain outside the city.
His second labor was to destroy the Lernaean Hydra, a serpent with nine heads and poisonous breath that lived in the swamps and ravaged crops and cattle. Having flushed the Hydra out of its lair Heracles attempted to club off its heads, but for every head that fell two grew in its place. With the help of his nephew Iolaus, who branded the severed necks, Heracles was able to kill the monster. He used the Hydra's blood to poison his arrows.
The third labor was to capture a deer with golden horns that lived on Mount Ceryneia and bring it back alive, an exploit that took Heracles a full year.
His fourth labor was to capture the wild boar of Erymanthus that was devastating nearby lands. On this expedition Heracles was treated hospitably by the Centaur Pholus, who opened a barrel of wine for him. But then other Centaurs savagely demanded it, and Heracles had to rout them with arrows. When he brought the boar back, Heracles showed it to Eurystheus, who was so terrified that he hid.
The fifth labor was to clean the Augean stables in one day. Since Augeas had thousands of cattle and their stables had not been cleaned for years the job seemed incredible, but Heracles diverted two rivers into the stalls that promptly cleaned the mess.
