List of countries by Iranian population in 2015

 The empire reached the peak of its power between the 15th and 17th centuries, especially during the 1520–66 reign of Suleiman the Magnificent. After the second Ottoman siege of Vienna in 1683 and the end of the Great Turkish War in 1699, the Ottoman Empire entered a long period of decline. The Tanzimat reforms of the 19th century, which aimed to modernize the Ottoman state, proved to be inadequate in most fields, and failed to stop the dissolution of the empire. The Ottoman Empire entered World War I (1914–18) on the side of the Central Powers and was ultimately defeated. During the war, major atrocities were committed by the Ottoman government against the Armenians, Assyrians and Pontic Greeks.