Political map of Sub-Saharan Africa 07 August 1916 (East African Campaign): By March 1916 the Allies (Allies of World War I) had conquered all of the German colonial empire except for German East Africa. That month, reinforced by veteran South African units (South West Africa campaign), the British and Belgians launched a multi-pronged offensive to overrun this last enemy colony, invading the territory from British East Africa, Northern Rhodesia, the Belgian Congo, and Uganda (East African Campaign (World War I)).