On July 24, 1922, the League of Nations confirmed the British mandate in Palestine, over territory that had belonged to the Ottoman Empire before World War I. The United Kingdom had already managed to occupy Palestine during that war, but the League of Nations mandate also gave it legitimacy to control the area in terms of international law. These were important factors for the later realization of the Jewish state, which was hinted at in 1917 by the British Prime Minister Balfour in the so-called Balfour’s declaration.
In addition to Palestine in the narrower sense, the British mandate included the area across the Jordan River, called Transjordan (the area of today’s Jordan). The French, on the other hand, received a mandate from the League of Nations over the territory of Syria and Lebanon. Such a demarcation between the British and French mandates was agreed in principle as part of the so-called Sykes-Picot Agreement of 1916.
The first British High Commissioner for Palestine was Sir Herbert Louis Samuel (later known as Lord Samuel), who was of Jewish descent. By the end of the British mandate in 1948, some 400,000 Jews had immigrated to Palestine, but it is not clear whether the British really counted on a Jewish state to be created then.
The problem arose because the British made several conflicting promises during the First World War regarding the fate of Ottoman possessions in the Middle East. Prior to the Sykes-Picot agreement, they agreed in the so-called McMahon-Hussein’s correspondence that much of that territory would belong to the sheriff of Mecca and other Arab rulers after the end of the war. This means that the Sykes-Picot agreement was in a way a betrayal of Arab interests and paved the way for the conflict between Arabs and Jews that continues today.