Answer:
Fall of the Eastern Roman Empire, Contributing to modern day turkey and possibly increase in islam in certain parts of the world.
Explanation:
During the crusades byzantine aka eastern roman empire was still around and the crusaders being well mostly random people raidedthe eastern roman empire (it was way closer than jeruslam) a lot more and contirubted to it becoming weaker and weaker and eventually the rise of the ottoman empire which is now modern day turkey in which islam spread throughout the middle east and the balkans.
(Also note not all crusades happened in the middle east you had pagans in iberia and eastern europe this can contribute to the formation of spain and possibly russian orthodoxy.)
