Consequences for the Middle East were far-reaching. Islam itself was transformed by the rise of Sufism. How much the Sufis owed to the pagan past of Turkic converts to Islam is unclear, though some practices of dervish orders, which were the main carriers of the Sufi movement, very likely did stem from shamanistic rites and practices of the steppes. In any case, Turkic languages were added to the Arabic and Persian that had previously been the carriers of Middle Eastern high culture; and a proud Turkic consciousness persisted among soldiers and rulers to complicate older ethnic patterns within the heartlands of Islam.

By submitting to Turkic warriors, the realm of Islam acquired a new cutting edge. Rapid expansion at the expense of both Christendom and Hindustan resulted. Raids into India, beginning in the year 1000, led within two centuries to the establishment of Muslim control over the plains of the north. Expansion continued off and on until, by the end of the 17th century, the whole of India had been subjected to Muslim overlordship. On the other flank of Islam, a decisive breakthrough occurred in 1071 when Seljuq tribesmen defeated the Byzantines at Manzikert (modern Malazgirt), thereby confirming their occupation of the grasslands in the interior of Asia Minor. Thus, modern Turkey became Turkish for the first time. This expansion triggered the First Crusade (1095–99), but the Crusaders’ success only checked, without permanently stemming, the Turkish advance. Instead, toward the end of the 13th century the Ottomans succeeded the Seljuqs as leaders of the struggle against Christendom and continued to advance their frontiers as late as 1683, by which time all of the Balkans and Hungary were under Turkish rule.

Muslim principles deplored strife among the faithful while admiring military success against unbelievers. This belief encouraged newcomers from the steppes to migrate toward the two expanding frontiers of Islam, where they could exercise their military skills, expect rich booty, and win new lands while enjoying the respect and admiration of fellow Muslims. As a result, the mainstream of steppe migration gravitated toward Islam’s Christian and Indian frontiers. Arab tribesmen had done the same in the Middle East and North Africa during the first century (632–732) of Muslim history. Thus, after about 900, the military manpower and skills of the northern nomads took over the role that had been played by Bedouins from the south during Islam’s first, extraordinary period of expansion.

Developments on the steppe proper

The tribes that remained behind on the Eurasian Steppe were of course affected by this massive Turkic influx into the Middle East. Trade connections with Islamic lands intensified, and traders from Middle Eastern cities spread Islam far and wide among steppe peoples. To be sure, full compliance with Muslim law was scarcely compatible with pastoral routines of life; but after the 11th century most of the Western Steppe had become, at least superficially, incorporated into the realm of Islam. Along with the religion, heightened familiarity with civilized ways penetrated deep into the steppe. Miniature cities arose at river crossings and at the headquarters of powerful chieftains, where merchants gathered and urban artisan skills began to find limited scope.

In the Eastern Steppe, Chinese civilization played the same role, although the oasis cities of the Tarim Basin continued to offer steppe peoples alternatives to a purely Chinese pattern of higher culture until long after this period. Collapse of the Kök Türk (Chinese Tujue) empire in 734, swiftly followed by a drastic weakening of the Tang dynasty after a massive rebellion in 755, hastened rather than hindered the infiltration of new skills into the Eastern Steppe. The Tang dynasty recovered control of China only by calling on barbarians for aid, which they received from a newly powerful Uyghur confederacy (745–1209) that had started as one of the successor states to the older Kök Türk empire of the steppes. But the Uyghur horsemen who rescued the Tang dynasty from its domestic difficulties did so only in return for handsome trade-tribute payments. Once begun, the flow of tribute from China continued as long as Uyghur power endured. The Uyghurs, of course, consumed some of the goods they carried out of China themselves but traded the rest with neighbours and neighbours’ neighbours for grain, slaves, and special goods such as jade, gold, and furs. A far-flung caravan network thus attained greater importance than ever before, binding steppe peoples to oasis cultivators in the south and forest peoples in the north and joining the parallel Muslim trade net of the Western Steppe.

Such exchanges involved more than simple export and import of goods. Religions continued to travel the caravan routes as they had done for centuries. Buddhism rivaled Islam in the Eastern Steppe, but the Uyghurs, interestingly, asserted and maintained their spiritual independence of both of the great civilizations they touched by espousing the Manichaean faith. They also used a Sogdian script, derived from Persian, that supplanted the Kök Türki runic script and allowed them to create a more thoroughly literate society than earlier steppe peoples had attained.