The Elamites 2400 B.C. - 644 B.C.
The Elamite empire was the first empire in Persia, including Khuzestan and the areas to the north and east.
The Elamite form of government was the system of inheritance and power distribution. The overlord lived in Susa, the city that acted as capital. The overlord ruled with his younger brother closest in age, called the viceroy. A third official, called the Prince of Susa, ruled with the viceroy and the overlord. The Prince was usually the son of the overlord; if not, the nephew. If the overlord died, the viceroy would take his place. The viceroy's next brother would be the new viceroy, and the Prince would stay in office. Dispite a complicated system of government, the empire succeeded. Elam was in close relation with Sumer, Babylon, and Assyria. This relationship included trade, but also included war.
The Elam military was very inconsistent. The Elamites would win battles at times, but Elam was overrun by Assyria and Babylon on more than one occassion. Around 1100 B.C., King Nebuchadnezzar of Babylon against Elam. Babylon succeeded and Elam was overun. Thus began a long period of darkness that separates the middle and neo-Elamite periods.
In 742 B.C., Hubannugash came to reign as king. In the next 100 years, Elam had no choice but to give way to neo-Assyrian expansion. Between 692 and 639 B.C., in an effort to clean up a diplomatic and political mess that was intolerable for the Assyrians, Abshurbanipal's armies destroyed Susa. They tore down buildings and looted.