The fourth/tenth century saw a profound change in the political society of the Islamic world. The superficial characteristics of this are well documented and easy to recognize – the caliphate disintegrated into a bewildering variety of successor states. The Muslim sources present these states as being ruled by dynasties, the ‘Uqaylids of Mosul, the Marwanids of Mayya-f a-riqı¯n and so on, each of which tended to last for about a century, and many of which seemed to go through a similar cycle of emergence, expansion under a strong ruler and decay under his weaker successors. Modern scholarship has tended to take over this traditional perspective, and it often seems to the casual enquirer that these states were sort of political mushrooms, pop-up states whose appearance is unexplained and whose collapse was the result of personal feebleness on the part of decadent rulers. In reality, however, the successor states varied greatly in their organization and outlook and reflected closely the economic and social structure of the society which produced them; it is only by concentrating on at least some of them in detail that we can see how the changes of this time affected the Muslim world.