At the time of Muhammad's death in 632, the Muslim community was still confined to the Arabian Peninsula and concentrated in the two towns of Mecca and Medina. Within a hundred years, Islam had spread from there to encompass Spain, the Maghrib, Egypt, Palestine, Syria, Iraq, Iran, Transoxania, and northwestern India. Within this area there were initially few Muslims, but over time the majority of the population converted. This rapid expansion subjected the political organization of the Muslim community, the caliphate, to powerful centrifugal forces that it was not equipped to handle. By the 900s, the caliphate had for all practical purposes split into a number of independent sultanates, although the caliph remained a potent symbol of religious community.

Beginning in the 900s, Turkish tribes migrated south and west off the steppe into the settled regions of Islamdom. Thanks to the missionary work of Sufi mystics and others, these tribes had generally converted to Islam beforehand. Still, this migration had profound effects on Islamdom, especially in regions like Anatolia, Azarbayjan, Khurasan, and Afghanistan that were suited to nomadic pastoralism. The balance between settled and nomadic shifted toward the latter. Thanks to their military prowess, the Turks were able to found dynasties all throughout Islamdom, even in places farther removed from the steppe like Egypt and India.

The invasion of the Mongols in the 1200s was more traumatic. Not only had the invaders not been converted to Islam, but they also sacked Baghdad and killed the caliph in 1258.