In Greek mythology, Proteus (/ˈproʊtiəs, ˈproʊt.juːs/ PROH-tee-əs, PROHT-yooss;[1] Ancient Greek: Πρωτεύς, romanized: Prōteús) is an early prophetic sea god or god of rivers and oceanic bodies of water, one of several deities whom Homer calls the "Old Man of the Sea" (hálios gérôn).