In Islam, there are two separate sects. The Sunni, which is the more popular of the two, believes that the first four caliphs were all rightfully there and that they were the successors of Muhammad. The Shiites believe that only direct descendants of Muhammad can be his successors, starting with the fourth caliph. This politically divided Islam into two separate groups. Today Islam is made up of approximately 80% Sunni, 15 % Shi'a, and 5% smaller other sects of Islam. The Shi'a is usually thought of as the more radically group.