caused by religious differences between 16th and 18th centuries.
From the beginning of the 19th century onwards, the Ottoman Empire began to decline. As it gradually shrank in size, military power, and wealth, many Balkan Muslims migrated to the Empire's heartland in Anatolia, along with Circassians fleeing the Russian conquest of the Caucasus. The decline of the Ottoman Empire led to a rise in nationalist sentiment among the various subject peoples, leading to increased ethnic tensions which occasionally burst into violence, such as the Hamidian Massacres. The Ottoman Empire entered World War I on the side of the Central Powers and was defeated. During the war, an estimated 1.5 million Armenians were deported and exterminated in the Armenian Genocide. The Turkish government denies that there was an Armenian genocide and claims that Armenians were only relocated from the eastern war zone. Large scale massacres were also committed against the empire's other minority groups such as the Greeks and Assyrians. Following the Armistice of Mudros on 30 October 1918, the victorious Allied Powers sought to partition the Ottoman state through the 1920 Treaty of Sèvres.
Republic
The occupation of Constantinople and Smyrna by the Allies in the aftermath of World War I prompted the establishment of the Turkish national movement. Under the leadership of Mustafa Kemal Pasha, a military commander who had distinguished himself during the Battle of Gallipoli, the Turkish War of Independence was waged with the aim of revoking the terms of the Treaty of Sèvres.
By 18 September 1922, the occupying armies were expelled, and the new Turkish state was established. On 1 November, the newly founded parliament formally abolished the Sultanate, thus ending 623 years of Ottoman rule. The Treaty of Lausanne of 24 July 1923, led to the international recognition of the sovereignty of the newly formed "Republic of Turkey" as the successor state of the Ottoman
