After death of Muhammad, his community needed to appoint a new leader, giving rise to the title Caliph, meaning "successor". Thus the subsequent Islamic empires were known as Caliphates. Alongside the growth of the Umayyad empire, the major political development within Islam in this period was the sectarian split between Sunni and Shi'ite Muslims; this had its roots in a dispute over the succession of the Caliphate. Sunni Muslims believed the caliphate was elective, and any Muslim might serve as one. Shi'ites, on the other hand, believed the caliphate should be hereditary in the line of the Prophet, and thus all the caliphs, with the exception of Ali, were usurpers. However, the Sunni sect emerged as triumphant in most of the Muslim world, and thus most modern Islamic political movements (with the exception of Iran) are founded in Sunni thought.