Muslim scholars began obtaining Greek treatises and started
their study and translation into Arabic a few centuries after
the Hijrah (622 A.D.) They critically analyzed, collated , corrected
and supplemented substantially the Greek science and philosophy.
After this period began what is known as the Golden Age
of Islam, which lasted for over two centuries. It is here we find
many of the great scientists of Islam who literally left behind
hundreds and thousands of books on the various branches of science.
Infectious diseases and colonization.
Sorry, I don't have an answer more specifc than that.
Generally speaking, industrialization greatly reduced social inequality by creating a "middle class" of people, who were able to significantly increase their incomes due to the large number of jobs available in factories.