A lot of people point to the post-WWI drawing of Middle Eastern borders as one of the primary causes for the conflict we see today. The Sykes-Picot Agreement negotiated by France and England dealt with how to dissolve the Ottoman Empire and led to “the division of Turkish-held Syria, Iraq, Lebanon, and Palestine into various French- and British-administered areas.”
These lines were drawn arbitrarily with little regard for culture or religion. Here for a quick primer on this agreement is Jon Stewart and his friend, Sir Archibald Mapsalot III:
http://www.cc.com/video-clips/kovgs5/the-daily-show-with-jon-stewart-sir-archibald-mapsalot-iii