The main task of the Mandates Section, first called "Mandatory Section" was to prepare the work and documents for the Permanent Mandates Commission and supply it with experts. It also prepared the work for the Council and the Assembly in the field of mandates and slavery. The Mandates Section dealt with slavery questions since 1922. It already used to deal with this kind of problem through questions such as colonial or race problems.
The Permanent Mandates Commission was established in February 1921. It received and examined the annual reports of the Mandated Powers and petitions relating to mandated territories. It was on the basis of these reports that the Commission advised the Council as to whether or not the conditions of each mandate were being strictly observed. It also assisted the Council in supervising all matters related to this issue. It was also responsible for securing the well-being and development of the peoples who inhabited the territories in question.
In 1939, the Section was merged into Department I.
Among the political, administrative and humanitarian tasks with which the League of Nations found itself entrusted under the terms of the Covenant itself, was that of supervising the tutelary administration of the colonies and territories which, as a consequence of the first world war, had ceased to be under the sovereignty of the States which had formerly governed them, and which were inhabited by "peoples not yet able to stand by themselves under the strenuous conditions of the modern world".
The Peace Conference of 1919 decided that these territories should be ruled by mandate. Under Article 22 of the Covenant, "... the well-being and development of such peoples form a sacred trust of civilisation... The best method of giving practical effect to this principle is that the tutelage of such peoples should be entrusted to advanced nations who, by reason of their resources, their experience or their geographical position, can best undertake this responsibility... this tutelage should be exercised by them as Mandatories on behalf of the League". The British Empire, France and Belgium were entrusted with the governance of the mandated territories.
Three categories of mandates, "A", "B", "C", were applied "according to the stage of the development of the people, the geographical situation of the territory, its economic conditions and other similar circumstances" (Article 22 of the Covenant).
In administering the territories in question, the Mandatories were to observe certain principles laid down in general terms in the Covenant and further defined in the mandates adopted by the Council of the League of Nations. The Covenant also laid down that the Mandatories were to render to the Council an annual report on the administration of the territories committed to their charge.
Under the United Nations, the work of the Mandates Commission continued through the Trusteeship Council, though it was no longer composed of non-governmental representatives. However, as the previously-mandated countries have become officially recognized as sovereign and independent States, its responsibilities have steadily diminished.