In striking contrast to the history of Mesopotamia of which we often have a clear knowledge from cuneiform texts and excavations, the proto-history of the Iranian Plateau remains amazingly obscure. Who were the people that occupied it before the arrival of the Aryans? How did the Medes, who were mentioned in 836 BC, establish a Median Empire occupying generally what is now West Iran and South Azarbaijan with its capital at Ecbatana -the present Hamadan -in the 7th century? There are no explicit sources nor, as yet, any adequate archaeological data providing a definite answer to these questions. Our knowledge remains very scanty up to the point when the peoples of the plateau began to conquer countries with a written tradition. Median Empire extended from the Caspian Sea to the Zagros mountains.
The Medes were an Indo-European people who spoke an Iranian language closely akin to Old Persian. Some scholars claim they were an Aryanized people from Turan. Since there are no Median records, Assyrian and Greek sources must be relied upon for Median history. The Medes extended their rule over Persia during the reign of Sargon (died in 705 BC), were united under a tribal chief named Dieoces in 673 BC, and under Cyaxares captured Nineveh in 612 BC putting an end to the Assyrian Empire as well as centuries of war against the Assyrians; they were the first people subject to Assyria to secure their freedom. The dynasty continued until the rule of Astyages, when it was overthrown (550 BC) by Cyrus the Great and united with the Persian Empire. In the 2nd century BC Media became part of the Parthian kingdom .