The two rivers are the Tigris and the Euphrates- Flow south to the Persian gulf, Social classes in Sumerian civilization, civilization brought social classes on priests- than wealthy merchants- third=workers-on bottom= slaves- Captured in war culture, just change of leader-"Sargon bronze head" associated with this time. Done. Persian Empire | History channel | BBC Documentary 8. Done. Organized Central Governent span>. Done. Job specialization. social classes in the following ancient civilizations: Ancient Egypt, Ancient India, Ancient The Fertile Crescent, Mesopotamia, and the Persian Empire. The Achaemenid Persian Empire first expanded under the leadership of Cyrus the rebellious regions, growing the Achaemenid Empire to its greatest extent. Xerxes's failure to defeat the Greeks marked the end of Achaemenid expansion.