The myth associated with the foundation of the Nemea Games is the story of the death of the baby Opheltes, son of Lykourgos and Eurydike. When their son was born, Lykourgos consulted the oracle at Delphi in order to find out how to insure the health and happiness of his child. The Pythia proclaimed that the boy must not touch the earth until he had learned how to walk.
Upon his return to Nemea, Lykourgos assigned a slave woman, Hypsipyle, to care for his son. Sometime thereafter, the Seven Against Thebes passed through Nemea from Argos on their ill-fated mission. When they asked Hypsipyle for something to drink, she placed Opheltes on a bed of wild celery where he was killed by a serpent, thus fulfilling the prophecy. The Seven renamed the baby Archemoros (Beginner-of-doom), and held the first Nemean Games as funerary games in his memory. The story is depicted on a Roman period sarcophagus from Corinth.
Vestiges of these origins could be seen at the site of Nemea in the form of a Shrine of Opheltes (where a bronze figurine of the baby was discovered) and a Sacred Grove of cypress trees.
They were also embedded in the customs of the games: the judges wore black robes as a sign of mourning, and the crown of victory was made of wild celery. The myth also gives a justification for the control of site and games to reside with Argos, the home of the Seven.