PART THREE. Introduction

By 656/1258, the year in which Mongol mounts trampled to death the last reigning ʿAbbasid caliph of Baghdad, Islam was more than half a millennium old. Muslims had voyaged by camel, horse, and sailing ship to all but the most distant reaches of Africa, Asia, and Europe. Within the societies over which their political authorities presided, they had experimented with myriad configurations of social, political, and intellectual life. The situation of world Islam was thus altogether different from what it had been in the tenth century, when political fragmentation could still be seen as a disturbing aberration, let alone in