The Medes had also established a kind of alliance with another Iranian tribal group, the Persians. The Persians had settled in the southern areas of the Zagros, the old homeland of the Elamites, and their rulers styled themselves “kings of Anshan” (a former Elamite stronghold). Presumably to strengthen the bonds between the two people, the Median king Astyages married one of his daughters, Mandane, to the Persian king Cambyses I (600–559 b.c. ). Mandane gave birth to a son who would become one of the most celebrated rulers of all antiquity: Cyrus the Great. In 549 b.c. , Cyrus led a successful revolt against his grandfather Astyages, who was deposed, and created a unifi ed Persian-Median empire with himself as “great king, king of kings, king of the lands.” He then asserted his authority over the Iranian tribes to the east, defeated King Croesus of Lydia and annexed his kingdom (ca. 547 b.c. ), took over the Greek city-states of Ionia, and occupied Babylon (539 b.c. ). The rest of his life was mostly spent in attempting to pacify eastern Iran and defend its borders; he apparently died in 530 b.c. fi ghting off nomads from central Asia. Cyrus was a master of diplomacy and propaganda who ruled his empire, the largest the world had seen, with a light hand; he is reputed to have dealt magnanimously with defeated rivals and to have followed a policy of allowing subject peoples to retain their local religion and customs (the most famous example being the Jews who were released from captivity in Babylon and encouraged to rebuild the Temple in Jerusalem).
The empire founded by Cyrus is known either as the Persian Empire, after the Persian people and the name of their homeland (Persis, the modern province of Fârs), or the Achaemenid Empire, after Achaemenes, the reputed ancestor of the dynasty. Already impressive at the time of Cyrus’ death, this empire was further expanded by his son Cambyses (530–522 b.c. ), who conquered Egypt, and in many ways was perfected by Darius the Great (522–486 b.c. ), a (perhaps distant) kinsman who took over the throne as the result of a murky palace coup. Darius proved to be an extremely successful ruler. He put down numerous attempted rebellions, defended the frontiers against the threat of nomadic invasions, and created the sophisticated system of communication and administration necessary to hold together such a vast empire. Among the many achievements of his reign were the system of organizing the empire into administrative units known as satrapies , the Royal Road and postal service linking the capital and the provinces, a canal linking the Nile and the Red Sea, the introduction of coinage, promulgation of a new law code, standardization of weights and measures, reorganization of the army and creation of the elite guard known as the Immortals, and the adoption of a script for writing the Old Persian language.
Unfortunately, Darius is most often remembered, at least among non-Iranians, for initiating the unsuccessful and ultimately disastrous series of wars between the Persians and the Greeks. The landing of Persian forces that the Athenians repulsed at the Battle of Marathon (490 b.c. ) was, to Darius, probably little more than a punitive raid that went awry. The invasion of Greece under his son Xerxes (486–465 b.c. ) was a more serious affair and one that had more far-reaching consequences. After defeating the Spartans at Thermopylae and sacking Athens, Xerxes’ campaign also ended in failure at the great naval battle of Salamis in 480 b.c. and on land at Plataea the following year. The ensuing struggle between the Greeks and Persians culminated in the invasion and destruction of the Persian Empire (334–330 b.c. ) by Alexander the Great and a period of Greek rule under the Seleucids. After the Greek interlude, two more great Iranian empires eventually arose, the Parthians and the Sasanids.