Euthymenes

Euthymenes of Massalia was a Greek explorer from Massilia (Marseille), who explored the coast of West Africa as far, apparently, as a great river, of which the outflow made the sea at its mouth fresh or brackish. His published accounts have not survived, but seem to have been known, at least at secondhand, by Plutarch, who writes "Euthymenes the Massilian concludes that the Nile is filled by Oceanus and that sea which is outward from it, the latter being naturally sweet." Euthymenes thought that this river was the Nile, but the river in question may have been the Senegal.