In his recent God’s Battalions: The Case for the Crusades , Rodney Stark challenges the conventional notion that Islamic civilization was more advanced than Christendom’s in the early middle ages.   One part of his case is to show that much of Islamic civilization depended on the contributions of Jewish and Christian dhimmis .  Nestorian Christians in Syria and elsewhere, for instance, “acquired a reputation with the Arabs for being excellent accountants, architects, astrologers, bankers, doctors, merchants, philosophers, scientists, scribes and teachers.  In fact, prior to the ninth century, nearly all the learned scholars in the [Islamic areas] were Nestorian Christians.”

Stark also argues that when the Muslims took up the culture of conquered peoples, they often misused it.  They read Aristotle the way the read the Qur’an, as an infallible text: “This eventually led the philosopher Averroes and his followers to impose the position that Aristotle’s physics was complete and infallible, and if actual observations were inconsistent with one of Aristotle’s teachings, those observations were either in error or an illusion.”

He runs through a number of technical areas - transport, military technology, agriculture - and shows that the early medieval West was far more innovative than early medieval Islam. Most startling is his observation that “following the Muslim conquest of Egypt, the rest of North Africa, and Spain, the wheel disappeared from the whole area!” - replaced by camels, donkeys and horses.