The caliphate is an Islamic state governed by a caliph, or chief Muslim ruler, in accordance with sharia (Islamic law). The first caliphate, known as the Rashidun Caliphate, was formed in present-day Saudi Arabia directly following the death of the Islamic prophet Muhammad in 632 CE. The caliphate continued under different names and in different locations including Arabia, Southwest Asia, North Africa, Spain, and Asia Minor with little interruption until the end of the Ottoman Caliphate in 1924. ISIS unilaterally declared a caliphate in June 2014 after conquering broad swaths of territory in Syria and Iraq.

The Rashidun Caliphate lasted for approximately three decades between 632 and 661. During this time period—remembered by many Muslims as the “golden age”—the Rashidun caliphs established the first systems of Islamic governance and expanded Islam into new territories, including present-day Syria, Iraq, Egypt, Jordan, and Palestine. In the subsequent Umayyad Caliphate (661-750), Caliph Abd al-Malik erected the Dome of the Rock in Jerusalem and his son, Caliph al-Walid, seized territory across North Africa and the Iberian Peninsula.

The Abbasid and Ottoman Caliphates, the final major caliphates, saw their borders wax and wane as territory was conquered and lost. The Ottoman Caliphate was established by sultans of the Ottoman Empire in 1517 in order to consolidate Ottoman power, bolster the sultans’ legitimacy, and preserve some degree of power over former Ottoman lands. The Ottoman Caliphate, considered by many to be the last legitimate caliphate, was abolished by secular Turkish leader Kemal Ataturk in 1924—two years after the dissolution of the Ottoman Empire.

Today, civilians living within ISIS’s self-proclaimed caliphate are forced to abide by the terror group’s literalist interpretation of sharia with stringent corporal punishments for even minor infractions. In ISIS-controlled territory, drugs, alcohol, and cigarettes are banned, women must be escorted by a male companion when leaving the house, gays are thrown from rooftops, sexual slavery is encouraged, thieves are punished with amputations, and apostates face death. ISIS’s claim of a caliphate has been widely rejected outside of extremist circles sympathetic to the terror group.