TLDR impatient version; The muslim conquest was only possible because europe and

TLDR impatient version; The muslim conquest was only possible because europe and Persia had exhausted each other with war. The subsequent raiding of trade and piracy on the seas destroyed the capacity of europe and persia to conduct trade. Islam was spread because one had to pay a 30% tax NOT to practice islam. Each generation of middle eastern conquerors took control by the same means – joining the military and administration then taking it over by force. So islam succeeds by destroying teh trade of more advanced civilizations, destroying it’s institutions, reducing people to muslim levels of ignorance, and then parasitically living off the silk road which was the only means of trade across the ‘world island’.
When the turks took Constantinople and closed the ports toe Europe in order to do the same thing to europe, the Europeans invented the age of sail, destroyed the market for overland trade, ended the silk road as viable, and without the ability to parasitically live off that trade, the middle east have consistently fallen behind.

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