The Crusades created extreme hatred between Christians and Muslims and caused the downfall of Constantinople. Constantinople was sacked three times during the Crusades, twice by the Christian Crusaders, and lastly by the Muslim Crusaders. Its hard to see any good coming from the Crusades, but changes in warfare and technology did stem from the Crusades. The brilliant Muslim leader, Saladin, incorporated his learnings into the regions that he conquered, much like Alexander the Great did.