As we have seen, Assyria rose to power from a base in the Tigris and Euphrates River Valleys of Mesopotamia, which had seen many earlier empires. The Assyrians were defeated by a coalition that included not only a Mesopotamian power — Babylon — but also a people with a base of power in a part of the world that had not been the site of earlier urbanized states: Persia (modern-day Iran) (Map 2.3).

Iran’s geographical position and topography explain its traditional role as the highway between western and eastern Asia. Nomadic peoples migrating south from the broad steppes of Russia and Central Asia have streamed into Iran throughout much of history. (For an in-depth discussion of these groups, see Chapter 12.) Confronting the uncrossable salt deserts, most have turned either westward or eastward, moving on until they reached the advanced and wealthy urban centers of Mesopotamia and India. Cities did emerge along these routes, however, and Iran became the area where nomads met urban dwellers.

Among these nomads were Indo-European-speaking peoples who migrated into this area about 1000 B.C.E. with their flocks and herds. They were also horse breeders, and the horse gave them a decisive military advantage over those who already lived in the area. One of these groups was the Medes, who settled in northern Iran. With the rise of the Medes, the balance of power in western Asia shifted east of Mesopotamia for the first time.

In 550 B.C.E. Cyrus the Great (r. 559–530 B.C.E.), king of the Persians (another Indo-European-speaking group) and one of the most remarkable statesmen of antiquity, conquered the Medes. Cyrus then set out to win control of the shore of the Mediterranean and thus of the terminal ports of the great trade routes that crossed Iran and Anatolia and to secure eastern Iran from the threats of nomadic invasions. In a series of major campaigns Cyrus achieved both goals.

After his victories, Cyrus made sure the Persians were portrayed as liberators, and in some cases he was more benevolent than most conquerors. According to his own account, he freed all the captive peoples, including the Hebrews, who were living in forced exile in Babylon.

Cyrus’s successors continued the Persian conquests, creating the largest empire the world had yet seen. Darius (r. 521–486 B.C.E.) conquered Scythia in Central Asia, along with much of Thrace and Macedonia, areas north of the Aegean Sea (see Map 2.3). Darius began to call himself “King of Kings.” Invasions of Greece by Darius and his son Xerxes were unsuccessful, but the Persian Empire lasted another two hundred years, until it became part of the empire of Alexander the Great (see “How did Alexander the Great’s conquests shape society in the Hellenistic period?” in Chapter 5).

The Persians also knew how to preserve the peace they had won on the battlefield. To govern the empire, they created an efficient administrative system based in their newly built capital city of Persepolis. Under Darius, they divided the empire into districts and appointed either Persian or local nobles as administrators called satraps to head each one. The satrap controlled local government, collected taxes, heard legal cases, and maintained order. He was assisted by a council and also by officials and army leaders sent from Persepolis who made sure that he knew the will of the king and that the king knew what was going on in the provinces. The Persians allowed the peoples they conquered to maintain their own customs and beliefs as long as they paid the proper amount of taxes and did not rebel.

Communication and trade were eased by a sophisticated system of roads linking the empire from the coast of Asia Minor to the valley of the Indus River. These roads meant that the king was usually in close touch with officials and subjects, and they simplified the defense of the empire by making it easier to move Persian armies. The roads also aided the flow of trade, which Persian rulers further encouraged by building canals, including one that linked the Red Sea and the Nile.