In 1914, war broke out between the Allies – principally Britain and France – and Germany and its allies, including the Ottoman Empire. The inhabitants of Palestine were bystanders at the beginning of the War, but the Allies had their eyes on the Middle East, and started to plan how it should be divided up if they won the War.
Both Britain and France had interests in Palestine and Syria. Meanwhile, in Britain, the Zionist movement, which was committed to turn Palestine into a Jewish state, started lobbying British politicians to share their aims and agree to allow a Jewish nation to be formed in Palestine in any eventual peace settlement. This pressure resulted in a notorious letter, called the Balfour Declaration, which led to Palestine being turned into a Jewish state.