THE PERSIAN EMPIRE was one of the first of the world empires to emerge in the ancient Middle East, the first to unify several different peoples and cultures into one large heterogeneous state. Much of this work was achieved by the emperors Cyrus and Darius, who recognized the strength of diversity, picking the best of a variety of practices and customs and welding them into a system that worked best for the empire as a whole. The original Persian Empire endured only two centuries, but it set a standard to be emulated by successive large multinational states set up by the Greeks and the Romans for centuries to come. The name Persia comes from a specific province within the empire, in what is today southwestern Iran. Here, in Pars (or Fars), the people spoke a language related to other peoples in India and Europe, but different from the Semitic peoples of Mesopotamia to the west. The Persian tribes (or Parsis) lived in the hilly region between the great empires of the Medes to the east and the Babylonians to the west and were ruled by each of them at various times. Parsis were descended from tribes known as Aryans, which eventually gave its name to modern Iran. In about 559 B.C.E., a Persian leader, Cyrus, unified the tribes, and led a revolution that overthrew the Medes and took over all of their territory (most of modern-day Iran). Cyrus the Great (559–530) established the first major Persian dynasty, the Achaemenid Dynasty, and took the title shah, or king. Instead of oppressing their former rulers, the Persian rulers united the Parsis and the Medes into one people, incorporating the Medes’s strong central government rather than trying to re-create it from scratch. By 539, the combined armies of Persians and Medes had conquered not only neighboring Babylon, but parts of Asia Minor (Anatolia) and Central Asia as well.