Possibly more than anything else, internal conflicts have ravished religions. For religious or political reasons, these conflicts have created sects that are so different that they are almost different religions. Two of the many religions that have split due to internal conflicts are Islam and Christianity, although there are countless more. 
Islam has particularly seen the results of internal conflict. The main divisions of Islam originated due to politics, not religious differences. In fact, the central text of Islam, the Qur’an, specifically bans religious divisions, but that could not control politics. After Muhammad, the founder of Islam, died multiple people claimed that they were the rightful successor to power. This created divisions in Islam, such as the Sunni and the Shi’a, that still around today. Unfortunately, these groups have always struggled to live in peace and violence between the Islamic sects is common even today.
Christianity has also been subject to internal conflict dating back to the ancient Romans. In the year 1054 Christianity literally split in half due to both religious and political differences. In what is called the East-West Schism or the Great Schism, Christianity created its first two branches, Roman Catholic to the west and Greek Orthodox in the east. Other challenges to the Church came relatively quickly due to the new spirit of the Renaissance. Movements such as the Protestant Reformation lead to the formation of many sects of Christianity such as Lutheranism and Calvinism. Most of these sects are very different from original Christianity and are almost a different religion. The Protestant Reformation was largely dependent on geography because new reformers arose in different countries. This also has led to violence. One example is the tension in the United Kingdom that centers on Protestantism. Though violence has stopped recently, the violence can be traced back for centuries.