The fifth Labour of Hercules was to clean the Augean stables.
This assignment was intended to be both humiliating (rather than impressive, as had the previous labours) and impossible, since the livestock were divinely healthy (immortal) and therefore produced an enormous quantity of dung. These stables had not been cleaned in over 30 years, and over 1,000 cattle lived there. However, Hercules succeeded by rerouting the rivers Alpheus and Peneus to wash out the filth.
Augeas was irate because he had promised Hercules one tenth of his cattle if the job was finished in one day. He refused to honour the agreement, and Hercules killed him after completing the tasks. Hercules gave his kingdom to Augeas’ son Phyleus, who had been exiled for supporting Hercules against his father. According to the Odes of the poet Pindar,
Hercules then founded the Olympic Games: “the games which by the ancient tomb of Pelops the mighty Hercules founded, after that he slew Kleatos, Poseidon’s godly son, and slew also Eurytos, that he might wrest from tyrannous Augeas against his will reward for service done”
The success of this labour was ultimately discounted because the rushing waters had done the work of cleaning the stables and because Hercules was paid. Eurystheus, stating that Heracles still had seven Labours to perform, then sent Hercules to defeat the Stymphalian Birds.