A military officer in the Ottoman army, Mustafa Kemal Atatürk was the leader of the Turkish national resistance movement and the founder and first president of the Republic of Turkey. After the Allies defeated the Ottoman Empire in World War I and started partitioning its territories, in 1919 he began to lead a national resistance movement in Anatolia. In 1920 he organized a provisional national assembly in Ankara, functioning independently from the Ottoman administration. Having successfully liberated Anatolia and eastern Thrace from foreign occupation as a result of the Turkish War of Independence (1919–1923), he founded the Republic of Turkey (1923), with himself elected by the assembly as its first president (1923–1938). He institutionalized political, economic, social, legal and educational reforms aimed at modernizing and secularizing Turkey and forging a new national identity. These included the abolishment of the caliphate (1924), the secularization and nationalization of education (1924), the adoption of new civil, commercial, and penal codes based on European models (1926), and the replacing of Arabic script with the Latin alphabet (1928). The principles of his reforms, commonly referred to as Kemalism, have defined the fundamental characteristics of the Republic throughout most of its history: republicanism, nationalism, populism, secularism, statism, and revolutionism.