"It was the swift inheritance of a preexisting state—not Islam—that led to the demise of early democracy in the Middle East. As the Islamic conquerors spread outward from Arabia, they soon encountered more densely populated lands where people practiced an intensive and settled form of agriculture, a radically different environment from Arabia. In the territory that is now Iraq these lands were part of the Sasanian Empire, and in the century or so before the Islamic conquests the Sasanians had succeeded in creating a centralized bureaucracy to collect taxes from a fertile agricultural region that would come to be known as the Sawad—“The Black Land.” Faced with this inheritance, after deposing the Sasanian leadership, the Arab conquerors co-opted their bureaucracy. The result, in spite of protests, was that caliphs could now govern in an autocratic manner with little need for consultation. Succession to the caliphate became hereditary."