It could be said that the history of the Middle East since ca. 1000 A.D. is marked by the infiltration of Central Asian, mostly Turkic peoples who, having first been brought in for military purposes, over time acquired positions of political power. In later times, they came in ever greater numbers, no longer forcibly imported but moving in as conquerors, until they effectively ruled the entire realm of Islam.
Their penetration of the Islamic world had significant political, social, and economic repercussions. Comment, with historical examples.