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. 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 the nomadic groups 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 the Indo-European groups was the Medes, who settled in northern Iran. The Medes united under one king and joined the Babylonians in overthrowing the Assyrian Empire. With the rise of the Medes, the balance of power in western Asia shifted for the first time to the area east of Mesopotamia.

In 550 B.C.E., Cyrus the Great (r. 559–530 B.C.E.), king of the Persians and one of the most remarkable statesmen of antiquity, conquered the Medes. (See “Individuals in Society: Cyrus the Great.") Cyrus’s conquest of the Medes resulted not in slavery and slaughter but in the union of the two peoples. Having united Persia and Media, Cyrus set out to achieve two goals. First, he wanted 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. Second, he strove to secure eastern Iran from the pressure of nomadic invaders.

In a series of major campaigns, Cyrus achieved his goals. He conquered the various kingdoms of the Tigris and Euphrates Valleys, including Babylon in 539 B.C.E. Cyrus then swept into western Anatolia. Cyrus’s generals subdued the Greek cities along the coast of Anatolia, thus gaining him important ports on the Mediterranean. From there, Cyrus marched to the far eastern corners of Iran and conquered the regions of Parthia and Bactria in Central Asia, though he ultimately died on the battlefield there.

A text written in cuneiform on a sixth-century-B.C.E. Babylonian clay cylinder presents Cyrus describing the way in which the main Babylonian god Marduk selected him to conquer Babylon and restore proper government and worship. We do not know who actually wrote the text, but whoever did made sure to portray Cyrus as someone who triumphed as the result of divine favor, not simply military conquest, and honored the gods of the regions he conquered.

After his victories, Cyrus made sure that the Persians were portrayed as liberators, and in some cases he was more benevolent than most conquerors were. According to his own account, he freed all of the captive peoples who were living in forced exile in Babylonia, including the Hebrews. He returned their sacred objects to them and allowed those who wanted to return to Jerusalem to do so, and he paid for the rebuilding of their temple.

Cyrus’s successors continued Persian conquests, creating the largest empire the world had yet seen. In 525 B.C.E. Cyrus’s son Cambyses (r. 530–522 B.C.E.) subdued the Egyptians and the Nubians. At Cambyses’s death (the circumstances of which are disputed), Darius I (r. 521–486 B.C.E.) took over the throne and conquered Scythia in Central Asia, along with much of Thrace and Macedonia, areas north of the Aegean Sea. By 510, the Persians also ruled the western coast of Anatolia and many of the islands of the Aegean. Thus, within forty years, the Persians had transformed themselves from a subject people to the rulers of a vast empire that included all of the oldest kingdoms and peoples of the region, as well as many outlying areas (see Map 2.1). Unsurprisingly, 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 Chapter 4).

The Persians also knew how to preserve the empire they had won on the battlefield. Learning from the Assyrians, they created an efficient administrative system to govern the empire based in their newly built capital city of Persepolis near modern Shiraz, Iran. 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 the satrap knew the will of the king and that the king knew what was going on in the provinces. This system lessened opposition to Persian rule by making local elites part of the system of government, although sometimes satraps used their authority to build up independent power.

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. On the roads were way stations where royal messengers could get food and horses, a system that allowed messages to be communicated quickly, much like the famed pony express in the American West. These roads meant that the king was usually in close touch with officials and subjects. The roads also simplified the defense of the empire by making it easier to move Persian armies. In addition the system allowed the easy flow of trade, which Persian rulers further encouraged by building canals, including one that linked the Red Sea and the Nile.