Most people (including Muslims) have forgotten that the Muslim world used to capture and enslave large number of Christians on a regular basis. In fact, it was

Most people (including Muslims) have forgotten that the Muslim world used to capture and enslave large number of Christians on a regular basis. In fact, it was one of the drivers of the Crusades, an idea conveniently forgotten by Muslims who point at the Crusades as evidence of the West's hostility to Muslims. Enslaving others is, while not necessarily normal, not uncommon. The enlightenment really changed things around, which shows the power of ideas.