Mustafa Kemal Atatürk was an Ottoman and Turkish army officer, revolutionary statesman, writer, and the first President of Turkey. He is credited with being the founder of the Republic of Turkey. Atatürk was a military officer during World War I. Following the defeat of the Ottoman Empire in World War I, he led the Turkish national movement in the Turkish War of Independence. Having established a provisional government in Ankara, he defeated the forces sent by the Allies. His military campaigns gained Turkey independence. Atatürk then embarked upon a program of political, economic, and cultural reforms, seeking to transform the former Ottoman Empire into a modern, westernized and secular nation-state. The principles of Atatürk's reforms, upon which modern Turkey was established, are referred to as Kemalism.