Alpheus, the ancient name of the Ruphia, a river of Peloponnesus, which rises in southern Arcadia, and, flowing through Elis and the Olympian plain, discharges itself into the Ionian sea. The Alpheus, at a little distance from its source, twice disappears under ground, which gave rise to the myth of the god of the river, and the nymph Arethusa, whom Diana essayed to save from his embraces by transforming her into a fountain, and placing her in the Ortygian isle, near Sicily. The god made a passage for his river beneath the intervening sea, and commingled its waters with those of the fountain in Ortygia.