Political map of Sub-Saharan Africa on 15 Oct 1917 (World War I in Africa: Conquest of German East Africa), showing the following events: Fall of German East Africa; US declaration of war on Germany; Liberia enters World War I; Mahenge Offensive.

Conquest of German East Africa

World War I in Africa

Sub-Saharan Africa 1917.1015

Conquest of German East Africa

Great War in Africa, East African Campaign, colonial campaigns (15 October 1917)

Historical Map of Sub-Saharan Africa

By the beginning of 1917 the Allies had confined the German forces in East Africa to the bush country south of the Rufiji River. The British crossed the Rufiji in January but, plagued by supply problems and unable to match the generalship of the German commander Paul von Lettow-Vorbeck, took until November to complete the conquest.

Main Events

Fall of German East Africa

On 5 January 1917 the first British troops crossed the Rufiji River at Kibambabwe, German East Africa, establishing a bridgehead in the face of heavy German opposition. In the following months the British pushed southwards, but, hampered by disease, poor leadership, and logistical problems, continuously suffered disproportionate losses compared to Paul von Lettow-Vorbeck’s Schutztruppe. The conquest of German East Africa was eventually completed in late November, when Lettow-Vorbeck withdrew into Portuguese East Africa and the remaining German troops north of the border surrendered.

US declaration of war on Germany

On 2 April 1917, United States President Woodrow Wilson asked a special joint session of the US Congress to declare war on the German Empire. Congress obliged by declaring war on the 6th, with the resolution passing 82 to 6 in the Senate and 373 to 50 in the House.

Liberia enters World War I

Liberia declared war on Germany on 4 August 1917, expelling its German advisors and later seizing German assets. Apart from Monrovia being shelled by a German submarine in June 1918, Liberia would see little direct involvement in World War I. However, its unstable and disrupted economy—Liberia had depended on Germany for around 75% of its foreign trade before the war—received some relief by US Liberty Loans.

Mahenge Offensive

In 1916 the British and Belgian governments had agreed that Belgium would restrict its control in German East Africa to Ruanda and Urundi. The next year, however, saw continued British difficulties with supply chains, disease, and German guerrilla tactics as they attempted to advance beyond the Rufiji River. At British request, the Belgians consolidated the Force Publique at Kilosa and marched on the fortified Mahenge plateau, at the time controlled by twelve German companies. The Belgian capture of Mahenge forced the Germans to retreat southeast, but any further Belgian advances were stopped by the onset of the rainy season.

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