In antiquity, when the fame of a sanctuary spread beyond its immediate borders, it was believed that not only the sanctuary, but also its athletic competitions, were founded by gods and heroes and that they were the first to have taken part in the competitions. The beginnings of the Olympic games are lost, deep in the mists of time, but the myths concerning their foundation are many and varied and reflect the religious beliefs of the different peoples who inhabited the area.
One myth names the founder of the games as Heracles Idaeus, who came from Crete with his brothers, the Curetes, and organized a race with a wild olive branch as the prize. Another dominant tradition was that the competitions were organized by Pelops, son of Tantalus, after having beaten Oenomaus in a chariot race. According to other myths, the competitions were established by Zeus after he had beaten Cronus at wrestling, or by Apollo after he had beaten Hermes in a race and Ares in a boxing match. There is also a legend which says that the founder of the competitions was Clymenus of Crete, a descendant of Heracles Idaeus, and another declaring that the competitions were established by Heracles, the famous son of Alcmene. Diodorus informs us that after the end of the Argonautic expedition, Heracles suggested to the leaders and heroes who were preparing to return home that they should vow that if any of them needed help in the future, the others would come to their assistance, and that they should choose a prominent place somewhere in Greece and establish there competitions in honour of Zeus Olympius. The leaders delegated Heracles who chose the site of Olympia which was devoted to Zeus. He established horse races and gymnastic competitions, defined the prizes and the rules of the competitions and sent Theoroi (official representatives of the competition committee) to announce them in the towns.
The peaceful landscape of Olympia hosted the worship of many deities who followed, one after the other, embracing various mythological traditions which are now long forgotten in the depths of time. The data from excavations and mythological study show that the first inhabitants of this area made offerings to a female deity, Gaia, the wife of Uranus. Her sanctuary, the Gaion, was located at the southern foot of the Hill of Cronus which, as the name indicates, was devoted to Cronus, a god of Cretan origin. At the same time, besides Gaia, other gods were also prominently worshipped in the area: Cronus, Rhea, Themis and Heracles Idaeus, the sanctuaries of whom may have been gathered at the foot of the Hill of Cronus. One more important god or demon of the Eleans was Sosipolis, who had a temple in Olympia where he was honoured together with Eilithyia. He was a snake-like divinity who seems to have been very respected, as the Eleans were accustomed to invoking him as the guardian of oaths.