How were the three Islamic empires established, and what sorts of governments did they set up?

Before the Mongols arrived in Central Asia and Persia, another nomadic people from the region of modern Mongolia, the Turks, had moved west, gained control over key territories from Anatolia to Delhi in north India, and contributed to the decline of the Abbasid caliphate in the thirteenth century. The Turks had been quick to join the Mongols and were important participants in the armies and administrations of the Mongol states in Persia and Central Asia. In these regions Turks far outnumbered ethnic Mongols.

As Mongol strength in Persia and Central Asia deteriorated in the late thirteenth to mid-fourteenth centuries, the Turks resumed their expansion. In the late fourteenth century the Turkish leader Timur (1336–1405), also called Tamerlane, built a Central Asian empire from his base in Samarkand that reached into India and through Persia to the Black Sea. Timur campaigned continuously from the 1360s until his death in 1405, aspiring to repeat the achievements of Chinggis Khan. He did not get involved in administering the new territories but rather appointed lords and let them make use of existing political structures. His conquests were exceptionally destructive and benefited only Samarkand, where craftsmen and other specialists were forced to move to work for the new rulers. After his death, his sons and grandson fought each other for succession. By 1450 his empire was in rapid decline, and power devolved to the local level. Meanwhile, Sufi orders (groups of Islamic mystics) thrived, and Islam became the most important force integrating the region. It was from the many small Turkish chiefs that the founders of the three main empires emerged.