 The first of Heracles' twelve labours, set by King Eurystheus (his cousin), was to slay the Nemean lion.Heracles wandered the area until he came to the town of Cleonae.There he met a boy who said that if Heracles slew the Nemean lion and returned alive within 30 days, the town would sacrifice a lion to Zeus; but if he did not return within 30 days or he died, the boy would sacrifice himself to Zeus.