Sorry, the 'Destruction of Baghdad destroyed the learning' is categorically false. If you will look at history, Islamic scholars kept churning out knowledge quite a bit after the destruction, and in terms of academic achievements, it doesn't seem to have had a LOT of interruption. My history professor explained it this way: If Cambridge/Boston MA area were to disappear tomorrow, we would most definitely lose a LOT in terms of knowledge and research. It would however not be a beginning of a dark age. I have been led to believe that modern historians mostly agree that the traditional interpretation of the sacking of Baghdad as being the ending of the Islamic Enlightenment is mostly overblown.