Caliph
After the first four caliphs (Abu Bakr, Umar ibn al-Khattab, Uthman ibn Affan, and Ali ibn Abi Talib), the title was used by the Umayyads, the Abbasids, and the Ottomans, as well as by other dynasties in Southern Pakistan, Spain, Northern Africa, and Egypt. Most historical Muslim rulers simply titled themselves sultans or emirs, and the caliph himself often had very little real authority. The title was not used after the Republic of Turkey abolished the Ottoman caliphate in 1924.