re: adamp - again we do it, you m-f*****s
i'm not going to provide sources it is extremely well documented that the crusades resulted in a massive transfer of knowledge from east to west. europe had little to offer due to hundreds of years of bookburning and persecution by the vatican. even after the crusades science and knowledge was considered heresy in western europe whilst in the east it was encouraged and allowed to flourish.
advanced building techniques (eg domes and minarets) were unheard of in europe until after the crusades. similarly windmills. just do a google search if you want to find out more.
