Until the opening of the eleventh century CE, the eastern frontiers of the Islamic world had been fairly stable. The frontier region between what is now eastern Afghanistan and north-western India, essentially the Indus Valley, still remained fluid, and was now to form the springboard for Muslim expansion further into India under the Ghaznavids and Ghūrids. To the north-east, the ancient Iranian kingdom of Khwārazm on the lower Oxus and, above all, the equally Iranian Sāmānid emirate in Khurāsān and Transoxania, which flourished for almost two centuries, constituted bastions of Islamic faith and society against the peoples of the Eurasian steppes. See Map 1 for this chapter.

However, the years after c. 1000 CE witnessed for this region an irruption of peoples from the steppe and forest lands beyond these Islamic outposts of Khwārazm and Transoxania, first of Turks and then, in the second half of the twelfth century, of Mongols and Turco-Mongols in the shape of the Qara Khitay and then, after 1217, of Chinggis Khan’s hordes. New ethnic elements were thus injected into the eastern Islamic world, hitherto dominated ethnically mainly by Iranians, and politically and culturally by a symbiosis of the Persian and Arabic literary and governmental traditions. These incursions from Inner Asia had effects on the older Islamic lands – in the case of the Mongol invasions, cataclysmic ones – but in the longer term, the perdurable, absorptive powers of Islamic religion and culture exercised their effects on the incomers.