Islam has two main branches: Sunni and Shia. Sunnis make up the majority of Muslims worldwide, believing that the community should select its leaders. They follow the teachings of the Quran and the Hadith, which are records of the sayings and actions of the Prophet Muhammad. Shia Muslims, on the other hand, believe that leadership should stay within the Prophet Muhammad's family, specifically through his cousin and son-in-law, Ali. This branch has various sub-sects, with the largest being the Twelvers. Both branches share core beliefs but differ in practices and interpretations of Islamic teachings.