In 1897, the German Empire established a presence in Rwanda with the formation of an alliance with the king, beginning the colonial era.

By September, a large portion of German East Africa was under Belgian occupation reaching as far south as Kigoma and Karema and as far eastwards as Tabora all in modern-day Tanzania.

An administration, headed by a Royal Commissioner, was established in February 1917 at the same time as Belgian forces were ordered to withdraw from the Tabora region by the British.

The Belgian occupation force expanded labor conscription;[5] 20,000 men were drafted act as porters for the Mahenge offensive, and of these only one-third returned home.

[8] The Treaty of Versailles in the aftermath of World War I divided the German colonial empire among the Allied nations.

Belgium was allocated Ruanda-Urundi even though this represented only a fraction of the territories already occupied by the Belgian forces in East Africa.

[citation needed] Administratively, the mandate was divided into two pays, Ruanda and Urundi, each under the nominal leadership of a Mwami.

The reforms produced a dense road-network and improved agriculture, with the emergence of cash crop farming in cotton and coffee.

Belgian administrators were influenced by the so-called Hamitic hypothesis which suggested that the Tutsi were partially descended from a Semitic people and were therefore inherently superior to the Hutu who were seen as purely African.

[12] In this context, the Belgian administration preferred to rule through purely Tutsi authorities therefore further stratifying the society on ethnic lines.

An elite secondary school, the Groupe Scolaire d'Astrida, was established in 1929 but as late as 1961, shortly before independence arrived, fewer than 100 Africans had been educated beyond the secondary level.The policy was one of low-cost paternalism, as explained by Belgium's special representative to the Trusteeship Council: "The real work is to change the African in his essence, to transform his soul, [and] to do that one must love him and enjoy having daily contact with him.

The independence of the Belgian Congo in June 1960 and the accompanying period of political instability further drove nationalism in Ruanda-Urundi and the assassination of the UPRONA leader Louis Rwagasore, also Burundi's crown prince, in October 1961 did not halt the movement.

After this, the mandate was administered by a Governor (gouverneur) located at Usumbura (modern-day Bujumbura) who also held the title of Vice-Governor-General (vice-gouverneur général) of the Belgian Congo.