The schism started with many minor arguments. Such as the pope got captured. The kidnappers made him blind. So he tried to get help from the emperor in the east but he refused to help. So the pope had a friend Charlemagne which is a emperor in a different country. Charlemagne helped him and protected him.The pope wanted to thank him for his deed so he crowned Charlemagne as a holy roman emperor in the east. This made Emperor Leo very angry because he was supposed to be the emperor.Than the emperor disagreed about idols because you were not actually praying to God you were praying to a object. So he ordered the idols to be smashed.This made the pope mad so he excommunicated him from the churches in the west. So then Emperor Leo excommunicated the pope from the churches in the east.This is why we have many different forms of Christianity like roman catholic which was used in the west and orthodox which was used in the east.