The East African campaign in World War I was a series of battles and guerrilla actions, which started in German East Africa (GEA) and spread to portions of Mozambique, Rhodesia, British East Africa, Uganda, and the Belgian Congo. The campaign all but ended in German East Africa in November 1917 when the Germans entered Mozambique and continued the campaign living off Portuguese supplies.
The strategy of the German colonial forces, led by Lieutenant Colonel (later Major General) Paul von Lettow-Vorbeck, was to divert Allied forces from the Western Front to Africa. His strategy became less effective after 1917 when he was driven out of German East Africa. The campaign in Africa consumed considerable amounts of Allied money and war material that could have gone to other fronts.
The Germans in East Africa fought for the whole of the war, receiving word of the armistice on 14 November 1918 at 07:30 hours. Both sides waited for confirmation, with the Germans formally surrendering on 25 November. GEA became two League of Nations Class B Mandates, Tanganyika Territory of the United Kingdom and Ruanda-Urundi of Belgium, while the Kionga Triangle was ceded to Portugal.
Background
German East Africa
German East Africa (Deutsch-Ostafrika) was colonized by the Germans in 1885. The territory spanned 384,180 sq mi (995,000 km2) and covered the areas of modern Rwanda, Burundi and Tanzania (not including Zanzibar). The colony's indigenous population numbered seven and a half million and was governed by 5,300 Europeans. Although the colonial regime was relatively secure, the colony had recently been shaken by the Maji Maji Rebellion of 1904–1905. The German colonial administration could call on a military Schutztruppe ("Protection force") of 260 Europeans and 2,470 Africans, in addition to 2,700 white settlers who were part of the reservist Landsturm, as well as a small paramilitary Gendarmerie.
The outbreak of World War I in Europe led to the increased popularity of German colonial expansion and the creation of a Deutsch-Mittelafrika ("German Central Africa") which would parallel a resurgent German Empire in Europe. Mittelafrika involved the annexation of territory, mostly occupied by the Belgian Congo, to link the German colonies in East, South-west and West Africa. Such an annexation would allow Germany to dominate central Africa and would make Germany by far the most powerful colonial power in Africa.
The German colonial military in Africa was weak, poorly equipped and widely dispersed, with the largest military concentration in the German colonial empire being in East Africa. Although better trained and more experienced than their opponents, many of the German soldiers were reliant on obsolete weapons such as the Model 1871 rifle, which used black powder, giving away the position of the firer.
The militaries of the Allied powers also had similar problems of poor equipment and small size. Most colonial militaries were intended to serve as local paramilitary police for the repression of unrest or rebellion. They were neither equipped nor organized to fight against military forces of foreign powers.
German strategy
The objective of the German forces in East Africa, led by Lieutenant-Colonel Paul von Lettow-Vorbeck, was to divert Allied forces and supplies from Europe to Africa. By threatening the important British Uganda Railway, Lettow hoped to force British troops to invade East Africa, where he could fight a defensive campaign. In 1912, the German government had formed a defensive strategy for East Africa in which the military would withdraw to the hinterland and fight a guerilla campaign. The German colony in East Africa was a threat to the neutral Belgian Congo but the Belgian government hoped to continue its neutrality in Africa. The Force Publique was constrained to adopt a defensive strategy until 15 August 1914, when German ships on Lake Tanganyika bombarded the port of Mokolobu and then the Lukuga post a week later. Some Belgian officials viewed hostilities in East Africa as an opportunity to expand Belgian holdings in Africa; the capture of Ruanda and Urundi could increase the bargaining power of the De Broqueville government to ensure the restoration of Belgium after the war. During the post-war negotiation of the Treaty of Versailles, the Colonial Minister, Jules Renkin, sought to trade Belgian territorial gains in German East Africa for the Portuguese Congo, to gain Belgian Congo a longer coast.
Initial fighting, 1914–1915
Outbreak and early German attacks
The governors of the British and German East Africa wanted to avoid war and preferred a neutrality agreement based on the Congo Act of 1885, against the wishes of the local military commanders and their metropolitan governments. The agreement caused confusion in the opening weeks of the conflict. On 31 July, implementing contingency plans, the cruiser SMS Königsberg sailed from Dar-es-Salaam for operations against British commerce. Britain sent cruisers from the Cape Squadron to shadow Königsberg and be ready to sink her, but she narrowly evaded them. Britain declared war on 4 August; on 5 August, troops from the Uganda protectorate assaulted German river outposts near Lake Victoria.
On the same day, the British War Cabinet decided to send an Indian Expeditionary Force (IEF) to occupy East Africa and thereby eliminate its ports as bases for raiders. On 8 August, the Royal Navy cruiser HMS Astraea shelled the wireless station at Dar es Salaam. Astraea's captain then agreed to a ceasefire, on condition the town remained an open city. This agreement caused discord between Vorbeck and Governor Heinrich Schnee, his nominal superior. Vorbeck opposed and later ignored the agreement; Astraea's captain was also reprimanded for exceeding his authority. Before the Battle of Tanga, when the IEF attempted to land there, the Royal Navy felt obliged to give warning that they were abrogating the agreement, forfeiting surprise.
In August 1914, the military and para-military forces in both colonies were mobilised, despite restrictions imposed by the two governors. The German Schutztruppe in East Africa had 260 Germans of all ranks and 2,472 Askari, equivalent to the two battalions of the King's African Rifles (KAR) in the British East African colonies. On 7 August, German troops at Moshi were informed that the neutrality agreement was at an end and ordered to raid across the border. On 15 August, Askari in the Neu Moshi region engaged in their first offensive operation of the campaign. Two companies of Askari (300 men) seized Taveta, on the British side of Mount Kilimanjaro, with the British firing a token volley and retiring in good order. The Askari detachment on Lake Tanganyika raided Belgian facilities, seeking to destroy the steamer Commune and gain control of the lake. The Germans were unsure of the intentions of Portugal, which was not yet a British ally; on 24 August, German troops attacked Portuguese outposts across the Rovuma, causing a diplomatic incident which was only smoothed over with difficulty.
In September, the Germans began to raid deeper into British Kenya and Uganda. German naval power on Lake Victoria was limited to the gunboat Kingani, a tugboat armed with one pom-pom gun, which caused minor damage and made a great deal of noise. The British armed the Uganda Railway lake steamers SS William Mackinnon, SS Kavirondo, SS Winifred, and SS Sybil as improvised gunboats. They trapped Kingani, which was scuttled by the Germans. The Germans later raised Kingani, dismounted her gun, and used her as a transport. With Kingani disarmed and her "teeth removed, British command of Lake Victoria was no longer in dispute."
British land and naval offensive
To solve the raiding nuisance and to capture the northern, colonised region of the German colony, the British devised a plan for a two-pronged invasion. IEF "B" of 8,000 troops in two brigades, would carry out an amphibious landing at Tanga on 2 November 1914, to capture the city and gain control the Indian Ocean terminus of the Usambara Railway. In the Kilimanjaro area, IEF "C" of 4,000 men in one brigade would advance from British East Africa on Neu-Moshi on 3 November 1914, to the western terminus of the railroad (see Battle of Kilimanjaro). After capturing Tanga, IEF "B" would rapidly move north-west, join IEF "C" and mop up the remaining German forces. Although outnumbered 8:1 at Tanga and 4:1 at Longido, the Schutztruppe under Vorbeck prevailed. In the East Africa volume of the British official history (1941), Charles Hordern described the events as one of "the most notable failures in British military history".
Two regular army regiments fought in the East African campaign. The 2nd Battalion, Loyal North Lancashire Regiment arrived with Indian Expeditionary Force B the force that tried to capture Tanga and after this stayed on the border between British and German East Africa. The 25th (Frontiersmen) Battalion, Royal Fusiliers was raised for service in East Africa in early 1915 and served throughout the war. Colonists were supplied by Rhodesia in 1914–1915 including the 2nd Rhodesia Regiment, the Nyasaland Field Force and South African troops including the South African Expeditionary Force which arrived in February 1916.
Königsberg of the Imperial German Navy was in the Indian Ocean when war was declared. In the Battle of Zanzibar, Königsberg sank the old protected cruiser HMS Pegasus in Zanzibar harbour and then retired into the Rufiji River delta. After being cornered by warships of the British Cape Squadron, including an old pre-dreadnought battleship, two shallow-draught monitors with 6 inches (150 mm) guns were brought from England and demolished the cruiser on 11 July 1915. The British salvaged and used six 4 inches (100 mm) guns from Pegasus, which became known as the Peggy guns; the crew of Königsberg and the 4.1 inches (100 mm) main battery guns were taken over by the Schutztruppe and were used until the end of hostilities.
Lake Tanganyika expedition
The Germans had controlled the lake since the outbreak of the war, with three armed steamers and two unarmed motor boats. In 1915, two British motorboats, HMS Mimi and Toutou each armed with a 3-pounder and a Maxim gun, were transported 3,000 mi (4,800 km) by land to the British shore of Lake Tanganyika. They captured the German ship Kingani on 26 December, renaming it HMS Fifi and with two Belgian ships under the command of Commander Geoffrey Spicer-Simson, attacked and sank the German ship Hedwig von Wissmann. The Graf von Götzen and the Wami, an unarmed motor boat, became the only German ships left on the lake. In February 1916, the Wami was intercepted and run ashore by the crew and burned. Lettow-Vorbeck then had its Königsberg gun removed and sent by rail to the main fighting front. The ship was scuttled in mid-July after a seaplane bombing attack by the Belgians on Kigoma and before advancing Belgian colonial troops could capture it; Wami was later re-floated and used by the British.
Allied offensives, 1916–1917
British Empire reinforcements, 1916
General Horace Smith-Dorrien was assigned with orders to find and fight the Schutztruppe but he contracted pneumonia during the voyage to South Africa, which prevented him from taking command. In 1916, General Jan Smuts was given the task of defeating Lettow-Vorbeck. Smuts had a large army (for the area), some 13,000 South Africans including Boers, British, Rhodesians and 7,000 Indian and African troops, a ration strength of 73,300 men. There was a Belgian force and a larger but ineffective group of Portuguese military units based in Mozambique. A large Carrier Corps composed of African porters under British command, carried supplies into the interior. Despite the Allied nature of the effort, it was a South African operation of the British Empire. During the previous year, Lettow-Vorbeck had also mobilised personnel and his army was now 13,800 strong.
Smuts attacked from several directions, the main attack coming from British East Africa (Kenya) in the north, while substantial forces from the Belgian Congo advanced from the west in two columns, crossing Lake Victoria on the British troop ships SS Rusinga and SS Usoga and into the Rift Valley. Another contingent advanced over Lake Nyasa (Lake Malawi) from the south-east. All these forces failed to capture Lettow-Vorbeck and they all suffered from disease along the march. The 9th South African Infantry, started with 1,135 men in February, and by October its strength was reduced to 116 fit troops, with little fighting. The Germans nearly always retreated from the larger British troop concentrations and by September 1916, the German Central Railway from the coast at Dar es Salaam to Ujiji was fully under British control.