Shaykh al-Islām was used in the classical era as an honorific title for outstanding scholars of the Islamic sciences. It first emerged in Khurasan towards the end of the 4th Islamic century. In the central and western lands of Islam, it was an informal title given to jurists whose fatwas were particularly influential, while in the east it came to be conferred by rulers to ulama who played various official roles but were not generally muftis. Sometimes, as in the case of Ibn Taymiyyah, the use of the title was subject to controversy. In the Ottoman Empire, starting from the early modern era, the title came to designate the chief mufti, who oversaw a hierarchy of state-appointed ulama. The Ottoman Sheikh al-Islam performed a number of functions, including advising the sultan on religious matters, legitimizing government policies, and appointing judges.

A fatwa is a legal ruling on a point of Islamic law (sharia) given by a qualified Islamic jurist (faqih) in response to a question posed by a private individual, judge or government. A jurist issuing fatwas is called a mufti, and the act of issuing fatwas is called ifta'. Fatwas have played an important role throughout Islamic history, taking on new forms in the modern era.