During World War I British, French, and Belgian forces in Africa successfully defeated those of Germany in German held African territory. The conflict was quite arduous, however, especially in German East Africa where General Paul von Lettow-Vorbeck forces of 4,000 German and 12,000 African askari kept 250,000 British and colonial troops occupied.

The Allies had fought World War I against Germany and Ottoman Turkey on the joint understanding that they were not interested in annexing colonial territory – this was still maintained as late as 5 November 1918 in a pre-Armistice declaration, during the period when Germany was considering surrender.

However post-World War I peace negotiations revealed a desire by the Allies to retain German territory in Africa – and an accord was reached at the Paris Peace Conference, which was written into the Covenant of the League of Nations, signed on 28 June 1919. The Covenant described agreed principles for collective security of member states, international arbitration, limitations on arms, and most importantly for Africa, a system by which German colonies would be distributed between Allied states as mandates.

Article 22 of the Covenant described the conditions under which three different forms (Class A, Class B, and Class C) of mandate would be created. Article 23 further described general human rights which member states and those living in mandated territories must follow.

The mandating powers were required to "secure just treatment of the native inhabitants of territories under their control", "secure and maintain fair and humane conditions of labour for men, women, and children", maintain "public order and morals", "guarantee freedom of conscience and religion", end slavery, limit military development to policing and defense within the mandate territory, and take steps to prevent and control disease.

Only two of the three classes of mandate were considered appropriate to Africa.

League of Nations Class A Mandate Territories
A Class A mandate territory was considered advanced enough politically and economically that a provisional independence could be granted, albeit under the administration of a member state of the League of Nations¹ – "subject to the rendering of administrative advice and assistance by a Mandatory until such time as they are able to stand alone²." No African colony was considered advanced enough to be designated a Class a mandate – only former Turkish provinces of Iraq, Syria, Lebanon, and Palestine were included. All Class A mandates gained full independence by 1949.

League of Nations Class B Mandate Territories
A Class B mandate territory was not considered advanced enough politically and economically that independence could be recognized at that time, and thus they were placed under the administration of a League of Nations member state.

The mandatory authority was responsible for "the administration of the territory under conditions [would] guarantee freedom of conscience and religion, subject only to the maintenance of public order and morals, the prohibition of abuses such as the slave trade, the arms traffic, and the liquor traffic³" and that there be no military build-up and that there be no "military training of the natives" except for policing and defense. This form of mandate was applied to the former German colonies and protectorates in Africa: Togoland, Kamerun, and German East Africa.

Togoland was split one-third to two-thirds along a north-south line on 20 July 1922. The one-third to the west became British Togoland, and was administered from the Gold Coast. The two-thirds to the east became French Togoland (or just Togo) and was administered in it's own right as part of French West Africa.

Most of the German colony of Kamerun was mandated to France, with two small sections on the north-west border with Nigeria being administered by Britain (20 July 1922). British Cameroons was somewhat neglected, and there was a significant influx of people from Nigeria. French Cameroon was administered on the same basis as the rest of French equatorial Africa.

Most of German East Africa was mandated to Britain⁴ as Tanganyika (on 20 July 1922), with the small territory of Ruanda-Urundi (now Rwanda and Burundi) mandated to Belgium on 31 August 1923. Unlike neighboring Kenya, British administered Tanganyika didn't suffer an influx of European settlers – this was a significant (positive) factor when the country approached independence. In 1925 Belgium formed an administrative union between its Ruanda-Urundi mandate and the Belgian Congo. A small triangle of land to the south of German East Africa, the Kionga triangle was given over to Portugal, and added to their colony of Mozambique.

League of Nations Class C Mandate Territories
A Class C mandate territory was not considered capable of sustaining an independent state due to its sparse population, small size, remoteness, especially where the territory bordered on that of the mandatory authority. In Africa German South-West Africa (now Namibia) was given on 1 October 1922 as a Class C mandate to the Union of South Africa. (Elsewhere in the world New Guinea was mandated to Australia, Western Samoa to New Zealand, and the north-Western Pacific island to Japan.) Indigenous peoples in the territories were given the same safeguards as those in Class B mandated territories.

The mandates were theoretically supervised by the League of Nations permanent Mandates Commission, but in reality this was run by those countries which had been granted mandates. The system was replaced after World War II by UN trusteeships (in 1946).

¹ In reality this meant one of the Allied countries that fought in that region.
² Paragraph 4, Article 22 of the Covenant of the League of Nations.
³ Paragraph 6, Article 22
⁴Britain was at first reluctant to take the whole of Tanganyika as a mandate. According to Smith and Nöthling, North of the Limpopo: Africa since 1800 "control of the south [of Tanganyika] was … initially offered to Italy and when it refused, it was offered to the United States. Only after the Americans had also rejected the suggestion did the British, on the insistence of Smuts, agree to take over the [whole] territory as a B-mandate."