Median empire is the first organized government in Iran that was established around 708BC by Diocese. The capital of the empire was Ecbatana (today Hamedan) in the west of Iran which was later used as the summer center of the Achaemenid kings.
When the Assyrian kings conquered Susa, the Elamite capital, they tried to rule over other tribes of Iran including the Medians.
Later, Cyaxares together with the Babylonian king attacked Assyria and put an end to their empire. The medians were of great power in Iran and ruled western, southern and central parts of Iran and even the Persians who later founded the Achaemenid Empire were under their control.
The grandson of Astiages, the last Median king, was named Cyrus who was then king of Anshan. He gradually increased his power and in 559 BC the Median Empire was ended by Cyrus the great, the Achaemenid.
One of the famous Median monuments is the stone lion (Shir-e-Sangi) in Hamedan and several rock-carved tombs.