Slaves on Horses: The Evolution of the Islamic Polity - Patricia Crone - Google Books

https://books.google.de/books?id=fOu7XGjKmkAC

Slave soldiers are a distinctively Muslim phenomenon. Though virtually unknown in the non-Muslim world, they have been a constant and pervasive feature of the Muslim Middle East from the ninth century AD into modern times. Why did Muslim rulers choose to…