During the mandatory period following World War I Britain's attempts to implement the provisions of the Balfour Declaration and establish a ‘National Home’ for the Jews in Palestine encountered stubborn resistance from the local Arab population. As dissatisfaction mounted in the late 1930s, militant nationalists were able to mobilize popular support for the Arab cause and foster the growth of an opposition movement directed against the British. The most visible and significantleader of this movement was the Mufti of Jerusalem, Haj Amin el-Husseini.