To exact vengeance for Zeus having affairs, the goddess Hera cursed Hercules, who's only release from the torment was to put himself in the service of the Mycenaean King.  Hercules was tasked with twelve impossible tasks to complete, and the first was to kill the Nemean Lion.  After a long battle, Hercules was finally able to stun the Lion, and strangle the beast to death with brute force.  Hercules returned triumphantly to Mycenae with the carcass of the Lion on his shoulders.