At the post-World War I San Remo Conference in April, 1920 in Italy, former Ottoman-controlled territories were allotted as "mandates" among the victorious Allies. In August, The government of the Ottoman sultan signed the Treaty of Sèvres, renouncing all claims to non-Turkish territory. Syria became a mandate of France; Mesopotamia and Palestine became British mandates. The Treaty of Sèvres was replaced by the Treaty of Lausanne in 1923. The first British census of Palestine showed a population of 757,182, with 78% Muslim, 11% Jewish and 9.6% Christian.

In 1922 The League of Nations issued a mandate to Britain to temporarily administer Palestine on behalf of both the Jews and Arabs living there. According to the mandate, Britain "shall be responsible for placing the country [Palestine] under such political, administrative, and economic conditions as will secure the establishment of the Jewish national home ... and also for safeguarding the civil and religious rights of all the inhabitants of Palestine, irrespective of race or religion."