All the opulence and strength of the Ottoman Empire began to be put to the test of the so-called Russian-Turkish Wars in the nineteenth century, especially in the First World War (1914-1918). The decline and end of the Ottoman Empire must be understood from the context of the First War.
Between 1922 and 1923, the Conference was held in Lausanne, Switzerland. The discussions of this conference resulted in the separation between the sultanate and the caliphate, that is, between political authority and religious authority (caliph), and the immediate choice to end the former. This culminated in the escape of the last sultan, Mehmed VI. That would be the path to the creation of the Republic of Turkey, whose first president was Mustafa Kemal.