A term referring both to the Islamic institution of government led by the unifying office of Caliph as well as to the territories and people under his direct control. Until the death of Prophet Muhammad, Islamic lands were limited to the Arabian Peninsula. Under his immediate successors, however, an expansion to nearby territories proceeded quickly. Within a century after Muhammad’s death, Muslims controlled a territory stretching from the Indus River in the east through Persia, the Arabian Peninsula, Syria, Palestine, Egypt, North Africa, and across the Strait of Gibraltar, encompassing Spain in the west. The non-Muslim peoples living under the caliph’s rule were not forced to convert to Islam; however, the governors and major government figures in the provinces under caliphal control were Muslims, and various taxes and other limits were placed on non-Muslims. At various times, rival claims to caliphal authority caused separate contemporaneous caliphates to arise. For instance, the Spanish and North African caliphate of Córdoba arose as a continuation of the Umayyad caliphal line after revolutionaries established the Abbasid dynasty in Baghdad. Later, the Shia-controlled Fatimid caliphate, based in Cairo, claimed authority despite the Abbasid caliphate. Time and internecine warfare doomed the rival caliphates until only the Abbasids remained powerful enough to rule. The whole of the Muslim world was not included within the direct purview of the caliph; many far-flung Muslim kingdoms and empires were fully independent of caliphal authority. Nonetheless, most of these states swore at least nominal allegiance to the caliph and often used his name to further their own legitimacy or called on him when in need.
   After the demise of the Abbasid caliphs in Baghdad and later Ottoman victory over the Mamluks in Egypt in 1517, the caliphate became synonymous with the sultan and the Ottoman Empire. For the first time since the early centuries of the caliphate, authority and governance were completely centralized and encompassed significant areas inhabited predominantly by non-Muslims, such as Greece and Armenia. At the height of Ottoman power, the caliphate controlled Anatolia, large swaths of Eastern Europe, the Caucasus, the Middle East, and most of North Africa.
   By the seventeenth century, the caliphate was weakening as a result of expensive wars with its neighbors in Europe and Persia, as well as a fundamental lack of leadership on the part of the sultans. A series of Russo-Turkish wars hampered Ottoman efforts to expand and maintain power just as European technological advances began to overwhelm the increasingly anachronistic Ottoman military, political, and social structures. In the early nineteenth century, these factors resulted in dramatic losses in the caliphate’s territory through military defeat, independence movements, and European colonialism. By the end of the nineteenth century, the caliphate was reduced to holding only Anatolia, Syria, Iraq, Palestine, and small portions of Arabia.
   The caliphate was effectively impotent but held on for several more decades until it was officially disbanded in 1924 in the aftermath of World War I and the establishment of the secular Turkish state.
    Crone, Patricia, and Martin Hinds. God’s Caliph: Religious Authority in the First Centuries of Islam. Cambridge: Cambridge University Press, 1986;
    Karsh, Efraim, and Inari Karsh. Empires of the Sand: The Struggle for Mastery in the Middle East 1789-1923. Cambridge, MA: Harvard University Press, 1999;
    Yapp, M.E. The Making of the Modern Near East, 1792-1923. New York: Longman, 1987.

Encyclopedia of the Age of Imperialism, 1800–1914. 2014.