From my understanding. It started when the PLO were disliked by many because they had Lebanon as a base for war against Isreal. Started when PLO tried to assassinate some big christian leaders because the PLO were just not welcome for some of their actions, and when christians tried to answer back in the infamous incident (el bosta) the bus that was filled with palestinians. The christian militia stoped it and shot everybody on it. After the bus incident little fights started happening, slowly things got worth. Then the muslim lebanese came in. The lebanese chrisitans asked for the syrian to come in but later on they didn;t want them. The muslim fought agianst the christians. After that muslim fought muslim, christian fought christians, muslim and christian against muslim and christians, .....and etc. There were too many militia political party, and they changed their alliance like you change sockes. Everybody fought agianst everybody. France and American got in too. It's was just a big disgraceful mess