A form of international trusteeship devised by the League of Nations for the administration of former German and Ottoman colonies after World War I. In 1919 the League assigned a mandate for each territory to one of the Allied nations (principally, Britain and France). Marking an important innovation in international law, the mandated territories were neither colonies, nor independent countries, but were to be supervised by the League's Permanent Mandates Commission. The latter, however, had no means of enforcing its will on the mandatory power, which was responsible for the administration, welfare, and development of the native population until considered ready for self-government. Most mandated territories, with the important exceptions of Palestine and Namibia, had achieved independence by World War II. In 1946 the mandate system was replaced by the United Nations' trusteeship system for the remaining mandates.