Decline and modernization of the Ottoman Empire
Beginning from the late eighteenth century, the Ottoman Empire faced challenges defending itself against foreign invasion and occupation. In response to foreign threats, the empire initiated a period of tremendous internal reform which came to be known as the Tanzimat, which succeeded in significantly strengthening the Ottoman central state, despite the empire's precarious international position. Over the course of the nineteenth century, the Ottoman state became increasingly powerful and rationalized, exercising a greater degree of influence over its population than in any previous era. The process of reform and modernization in the empire began with the declaration of the Nizam-ı Cedid (New Order) during the reign of Sultan Selim III and was punctuated by several reform decrees, such as the Hatt-ı Şerif of Gülhane in 1839 and the Hatt-ı Hümayun in 1856. At the end of this period, marked with 1908, to a degree the Ottoman military became modernized and professionalized according to the model of Western European Armies. The period was followed by the defeat and dissolution of the Ottoman Empire (1908–1922).
Ottoman Caliphate
The Ottoman Caliphate (1517–1924), 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 Murad I's conquest of Edirne in 1362. Later 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.