Ismailis, make up the second largest branch of Shi‘i Islam after the Twelvers (Ithna ‘Ashariyyah). While all Muslims
recognize Prophet Muhammad as the last in a long line of Prophets and Messengers of God and the Qur'an as the
revelation of God's Word, there are differences of interpretation concerning the scope and locus of religious authority
after the death of Muhammad. Sunni Muslims vest religious authority in the Qur'an, the Hadith, and the interpretations
of these sources by the religious scholars (‘ulama) of the community; Shi‘i Muslims believe that the Prophet
Muhammad's divinely‐ordained spiritual authority, divinely‐inspired knowledge, and role in interpreting revelation
continues in members of his family, beginning with his cousin and son‐in‐law ‘Ali b. Abi Talib, and a specific lineage
of his descendants. This office of religious authority and leadership is called the Imamat (Imamah) and forms the core
doctrinal principle of the major branches of the Shi‘a—the Twelvers (Ithna Asharis), the Ismailis, and the Zaydis.