Map 4.4: Fragmentation of the Islamic World, c.1000
The key cause of the weakness of the Abbasid caliphate was lack of revenue.
When landowners, governors, or recalcitrant military leaders in the various regions of
the Islamic world refused to pay taxes into the treasury, the caliphs had to rely on the
rich farmland of Iraq, long a stable source of income. But a deadly revolt lasting from
869 to 883 by the Zanj—black slaves from sub-Saharan Africa who had been put to
work to turn marshes into farmland—devastated the Iraqi economy. Although the
revolt was put down and the head of its leader was “displayed on a spear mounted in
front of [the winning general] on a barge,” there was no chance for the caliphate to
recover.^4 In the tenth century the Qaramita (sometimes called the “Carmathians”), a
sect of Shi‘ites based in Arabia, found Iraq easy prey. The result was decisive: the
caliphs could not pay their troops. New men—military leaders with their own armies
and titles like “commander of commanders”—took the reins of power. They
preserved the Abbasid line, but they reduced the caliph’s political authority to
nothing.
The new rulers represented groups that had long awaited power. The Buyids, for
example, belonged to ancient warrior tribes from the mountains of Iran. Even in the
