The kingdom of Media was located in the region between the southwest Caspian sea and the Persian Gulf. Biblical sources, as well as Greek historians, often confused the Median kingdom with the nearby Persians. The Median tribe cooperated with the Babylonians but, in the 6th century BCE, were defeated by Cyrus of Persia.
Sources: Bridger, David. Ed. The New Jewish Encyclopedia. NY: Behrman House, Inc. 1976.
Schreiber, Mordecai (ed.). The Shengold Jewish Encyclopedia. Shengold Books. 1998.
Telushkin, Joseph. Jewish Literacy. William Morrow and Company, Inc. 1991.