Hercules was ordered to perform twelve labors as penance for killing his children during a fit of madness caused by Hera. The labors included killing the Nemean lion, slaying the Hydra of Lerna, capturing the Erymanthian boar, and cleaning the Augean stables in a single day. The final three labors were obtaining the belt of Hippolyta, stealing the cattle of Geryon, and capturing Cerberus from the underworld.