A Dictionary of Greek and Roman biography and mythology

(Σωσίπολις), i. e. the saviour of the state, was the name of a hero among the Eleans, who was represented as a boy wearing a military cloak, and carrying the horn of Amalthea in his hand. He had a sanctuary in common with Eileithyia at the foot of the hill of Cronos at Olympia, and no one was allowed to approach his altar except the priestess, and even she only with her head covered. Oaths in which he was called upon were considered to be particularly solemn and binding. The origin of his worship is thus related :--Once when the Arcadians had invaded Elis and the Eleans had marched out to meet them, there appeared among the Eleans a woman with a boy at her breast and declaring that after she had given birth to the child she had been called upon by a vision in a dream, to offer the child as a champion to the Eleans. The commanders of the Eleans believing the assertion, placed the child naked before their ranks, and when the Arcadians began the attack, the child was metamorphosed into a serpent. Hereupon the Arcadians fled in dismay, and the Eleans pursuing them gained the victory. The Eleans hence called their saviour Sosipolis, and on the spot where he had disappeared in the form of a snake they built a sanctuary to him and his supposed mother Eileithyia. (Paus. 6.20.2, 3.25.4.)

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