This chapter describes the series of empires that arose in Persia (modern-day Iran) and controlled much of the territory between the Mediterranean Sea and India for over one thousand years, from about 550 B.C.E. through 650 C.E. The first empire, founded by Cyrus the Achaemenid, expanded under him and his successors until it became the largest empire the world had ever seen. The four Persian dynasties of this era (Achaemenid, Seleucid, Parthian, and Sasanid) were noted for several important developments.
Tightly governed administration with networks of educated bureaucrats, tax collectors, and spies to maintain the order and the authority of the emperor
The development of qanats, underground canals, to support the economic foundation of the empires: agriculture
Sophisticated policies promoting long-distance trade such as standardized coinage, road building, a courier service, accessible marketplaces, and banks and investment companies
The emergence and elaboration of Zoroastrianism, a popular and influential religion whose teachings demanded high moral and ethical standards