Ottoman Caliphate  The Ottoman Caliphate, under the Ottoman dynasty of the Ottoman Empire, was the last Sunni Islamic caliphate of the late medieval and the early modern era. During the period of Ottoman growth, Ottoman rulers claimed caliphal authority since 1517 since Selim I, through conquering and unification of Muslim lands, became the defender of the Holy Cities of Mecca and Medina which further strengthened the Ottoman claim to caliphate in the Muslim world since 1517. The demise of the Ottoman Caliphate took place because of a slow erosion of power in relation to Western Europe, and because of the end of the Ottoman state in consequence of the partitioning of the Ottoman Empire by the League of Nations mandate. Abdülmecid II, the last Ottoman caliph, held his caliphal position for a couple of years after the partitioning, but with Mustafa Kemal's secular reforms and the subsequent exile of the royal Osmanoğlu family from the Republic of Turkey in 1924, the caliphal position was abolished. With the establishments of Bektashi and Mevlevi orders, heterodox, syncretic and mystic approaches to Islam like Sufism were flourished. Since Murad I's conquest of Edirne in 1362, the caliphate was claimed by the Turkish sultans of the Ottoman Empire. In 1517, the Ottoman Sultan Selim I defeated the Mamluk Sultanate in Cairo in the Ottoman–Mamluk War. The last Abbasid caliph, Al-Mutawakkil III, was brought back to Constantinople as prisoner. There, it is said, Al-Mutawakkil formally surrendered the title of caliph as well as its outward emblems—the sword and mantle of Muhammad—to Selim, establishing the Ottoman sultans as the new caliphal line. And they gradually came to be viewed as the de facto leaders and representative of the Islamic world. From Constantinople, the Ottoman sultans ruled over an empire that, at its peak, covered Anatolia, most of the Middle East, North Africa, the Caucasus, and extended deep into Eastern Europe. Strengthened by the Peace of Westphalia and the Industrial Revolution, European powers regrouped and challenged Ottoman dominance. Owing largely to poor leadership, archaic political norms, and an inability to keep pace with technological progress in Europe, the Ottoman Empire could not respond effectively to Europe's resurgence and gradually lost its position as a pre-eminent great power. In the nineteenth century the Ottoman Empire initiated a period of modernization known as the Tanzimat, which transformed the nature of the Ottoman state, greatly increasing its power despite the empire's territorial losses.