sentences:  Before World War I, the Middle East, including Palestine (later Mandatory Palestine), had been under the control of the Ottoman Empire for nearly 400 years.During the closing years of their empire, the Ottomans began to espouse their Turkish ethnic identity, asserting the primacy of Turks within the empire, leading to discrimination against the Arabs.The promise of liberation from the Ottomans led many Jews and Arabs to support the allied powers during World War I, leading to the emergence of widespread Arab nationalism.