East African campaign
The East Africa campaign was a theatre of conflict in the Second World War between the Kingdom of Italy and its colony in East Africa against the United Kingdom and its African holdings.
Interbellum
In October of 1935, Benito Mussolini launched an invasion of the Ethiopian Empire under Haile Selassie. Ethiopia had previously humiliated Italy in the first Italo-Ethiopian War, where Italy found itself outgunned and outnumbered by an African power they assumed was weak and incompetent. Mussolini intended to stage this second war in Abyssinia in order to rebuild Italian national pride. Ethiopia, however, put up staunch resistance to the Italian campaign, forcing the Italians to use chemical weapons - banned under the Geneva Convention. Ultimately, however, the isolated Ethiopia could not stand against the effort of Italy's modern military might and in 1937, Haile Selassie abdicated the throne. Victor Emmanuel III was crowned emperor in his place.
Italian East Africa was founded in 1937, following the annexation of the Ethiopian Empire. Mussolini intended for it to become the crown jewel of the Italian Empire. Given the Horn of Africa's strategic location to global shipments through the Suez Canal and the Red Sea, its position was much too valuable to abandon.
Defensive Campaign
During the Second World War the newly established Italian East Africa was left isolated, no longer able to receive reinforcements and supplies from the rest of the Axis due to the Suez Canal being closed to the Italians. Outgunned and outnumbered, the Italian colonial troops and the loyal Askari from Somalia, Eritrea and Ethiopia were forced to retreat in front of the heavy attacks from the combined English, French and Belgian attacks, especially since they completely lacked any air support, leaving them vulnerable to bombings and air strikes.
The more they retreated, however, the more the invaders overextended their supply lines, forcing them to slow their advance and redeploy troops behind the lines to protect supply convoys and depots. Compounding the logistical nightmare of the Allied advance was Ethiopia's labyrinthine maze of mountains, hills and passes, hostile to both tanks and air support while providing countless opportunities for ambushes. This had been against the Italians during their invasion previously, and now it would work in their favor. Under the competent command of the Viceroy Amadeo di Savoia-Aosta, the few Italian divisions and their local auxiliaries started to employ non-conventional tactics taking on more of the appearance of guerilla fighters, luring the enemy towards prepared traps, ambushing enemy patrols and raiding supply convoys for weapons and ammunition.
Colonial forces began to utilize captured British equipment to supplement their lost Italian equipment which had not been resupplied since the closure of the Suez. The Viceroy, however, knew that it was impossible for him to defend the entirety of the colony against the British due to a significant shortage of weapons, equipment, and manpower, causing him to slowly lose territory to the British in spite of his spirited defensive campaign.
Offensive Campaign
The collapse of France and its colonial divisions, as well as the complete destruction of the British army in Europe meant that the United Kingdom was forced to recall its military presence in its colonial territories to the British isles - to mixed success with the capture of Gibraltar later that year - meaning that the Viceroy no longer was outnumbered, allowing him to conduct more traditional offensives.
The first major offensive success the Viceroy would enjoy would be during the Battle of Bahir Dar, where an Allied logistics distribution center under construction would be seized just before the completion of construction by a combined Italo-Askari offensive; it is estimated that the majority of British rifles actively being used outside of the North Africa campaign were seized in the battle. The Viceroy's focus on small offensives centered around 'pestering' the enemy rather than pursuing ultimate victories meant that the allies were unable to muster a strong enough offensive in any one area to defend against.
In July of 1942, following their decisive victory in the Battle of El Alamein, the Italian and Germans broke through the Allies' front line and captured a key supply depot. In September, in the Battle of Alexandria, the remaining British colonial army was surrounded and, with nowhere to run, surrendered, leaving British Africa defended by a contingent numbering less than 19,000 men. While part of the Italian forces seized the Suez and the Levantine territories - joining forces with the Iraqi fascist uprising and securing its oil wells for the Axis - a plurality of the Italian troops went south into the interior of the British colonial possessions in Africa, capturing Sudan, and finally linking Italian Libya with the stranded East African colony. Reinforcements, supplies and air support allowed the Viceroy to break the siege and inflict a devastating defeat to the Allies at the Battle of Amba Alagi.
Consequences
The news that the colony had resisted for years, alone and outnumbered, was welcomed with amazement and pride by the Italian population, and the soldiers and Askari were celebrated as heroes of Fascism for their bravery against all odds. The Viceroy became a hero, and his name for a while became even more famous than that of the Duce - much to Mussolini's dissatisfaction. With the colony secured, Amadeo led the new colonial troops into the South, occupying much of the British colonies in Africa and securing the rich resources for the Axis industrial efforts.
East Africa increased its holdings, with the annexation of French Djibouti and some English territories West of Somalia as well as some of British East Africa (or 'Kenia'). The great help granted by the loyal Askari contributed towards a policy of respect and gratitude towards the local negri: racial laws forbidding inter-racial marriages were repealed, slowly creating an increasing "middle class" of mixed Italo-Ethiopians, loyal to the Empire and accepted by the locals. The Viceroy introduced civil and labour reforms that saw East Africa grow into the crown jewel - albeit an expensive one to maintain - of the Italian Empire.