The first of Hercules' historic Twelve Labors was to bring to King Eurystheus the skin of an invulnerable lion which roamed the land of Argolis, terrorizing the hills around Nemea. The birthright of this Nemean Lion varies according to which particular myth is consulted. According to some sources, this enormous and extremely ferocious beast was the offspring of a liaison between the 100-headed monster known as the Typhon and the half-maiden/half serpent called Echinda. Other sources state that the Nemean Lion fell to Earth from the Moon and was the offspring of Zeus (King of the Gods) and Selene (Goddess of the Moon). It is also suggested that Selene deliberately let the beast loose on the population of Nemea in Argolis because they did not pay her due homage. In addition, the Nemean Lion is credited with being the brother of the Theban Sphinx.

Regardless, Hercules began his first labor...a seemingly impossible task...by traveling to a town called Cleonae, where he stayed at the house of an impoverished workman-for-hire whose name was Molorchus. When Molorchus offered to sacrifice an animal in order to ensure a safe lion hunt, Hercules asked the workman to wait thirty days. Then, if the hero returned with the lion's skin, a sacrifice would be made to Zeus. However, if Hercules perished during the course of his quest, Molorchus agreed to make the sacrifice instead in honor of the deceased hero. Upon reaching Nemea, Hercules began to track the terrible lion. However, he soon discovered that arrows were useless against the creature. Picking up his club, Hercules followed the lion to a cave which had two entrances. Blocking one of the doorways, the hero approached the fierce lion through the other. Then, grasping the beast within his mighty arms and ignoring its powerful claws, Hercules held the lion tightly until he had choked it to death. Returning to Cleonae carrying the dead lion, Hercules reunited with Molorchus on the thirtieth day after his departure. Thus, instead of sacrificing to a deceased hero, Molorchus and Hercules were able to make a sacrificial offering together to the King of the Gods. When Hercules arrived back in Mycenea, Eurystheus was so amazed that the hero had managed to achieve such an impossible task that he grew fearful of Hercules and forbade him from entering through the gates of the City. Further, the King of Mycenea ordered that a large bronze jar be fashioned and buried partway in the ground, where he could hide from Hercules if the need arose. After that, Eurystheus communicated his commands regarding the future labors of Hercules through a herald, refusing to meet the intrepid hero face-to-face.

According to some versions of the tale, once the huge lion was dead, Hercules set about skinning the beast, but the hide was so tough that he could neither tear nor cut it. Then, he tried the enormous claws which were very sharp and managed to penetrate the skin, whereupon Hercules claimed his trophy. Realizing how impenetrable this pelt would be, he threw it over himself in the form of a cloak and, pulling the head over his own as a helmet, created from the hide an armor which would make this hero even more powerful than before...symbolically adopting the attributes of the lion to complete his remaing tasks. An alternative to the story of how the Nemean Lion was skinned states that Athene, in the guise of an ancient crone, eventually helped Hercules to realize that the best tool to cut the hide would be the beast's very own claws.

Hercules is often depicted on ancient Greek vase paintings or in sculptures wearing the skin of a lion...its jaws forming the peak of a helmet while the great clawed paws are knotted at the hero's chest, the whole forming a hooded cape. However, historians have traditionally disagreed as to whether the skin Hercules is portrayed wearing in such works of art is that of the Nemean Lion or that of different lion entirely...one which Hercules is said to have killed when he was eighteen years old. Indeed, the playwright Euripides wrote that Hercules' lion skin garb actually came from the Grove of Zeus, also known as the Sanctury at Nemea.

Later, it is said that it was Zeus who hung the lion's likeness in the heavens. There, the creature slain by Hercules spends much time snoozing in his den. Despite his fangs, he is perceived as a friendly and affectionate beast...a loving father to his cubs and most protective of his lioness.