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 (r. 1789-1807) 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 defeat and dissolution of the Ottoman Empire (1908–1922).
The rise of nationalism swept through many countries during the 19th century, and it affected territories within the Ottoman Empire. A burgeoning national consciousness, together with a growing sense of ethnic nationalism, made nationalistic thought one of the most significant Western ideas imported to the Ottoman Empire. The empire was forced to deal with nationalism from both within and beyond its borders. The number of revolutionary, secret societies which turned into political parties during the next period rose dramatically. Uprisings in Ottoman territory had many far-reaching consequences during the 19th century and determined much of the Ottoman policy during the early 20th century. Many Ottoman ruling elite questioned whether the policies of the state were to blame: some felt that the sources of ethnic conflict were external, and unrelated to issues of governance. While this era was not without some successes, the ability of the Ottoman state to have any effect on ethnic uprisings was seriously called into question.