Army of the Ethiopian Empire in the context of "Tekle Haymanot of Gojjam"

On 12 September 1974, Emperor Haile Selassie was deposed by the Coordinating Committee of the Armed Forces, Police, and Territorial Army, a military junta that consequently ruled Ethiopia as the Derg until 28 May 1991.

In February 1974, the Ethiopian Revolution was accompanied by mutinies of units of the Imperial Army, which were ignited over resentment of low payment. The Derg established the Coordinating Council of the Armed Forces in June 1974, and grew rapidly to topple the ministers of Haile Selassie under Prime Minister Endelkachew Makonnen. Upon deposing the emperor, many of his personages and Imperial family members fled to London like Crown Prince Asfaw Wossen. On 27 March 1975, the Derg officially abolished the monarchy and the Ethiopian Empire as a whole, and began implementing a Marxist-Leninist system, along with nationalizing all properties. Haile Selassie died on 27 August, with different sources attributing his death to strangulation by the order of the military government or natural causes during a prostate operation.

The Derg or Dergue (Amharic: ደርግ, lit. 'committee' or 'council'), officially the Provisional Military Administrative Council (PMAC), was the military junta that ruled Ethiopia, including present-day Eritrea, from 1974 to 1987, when they formally "civilianized" the administration, though remaining in power until 1991.

The Derg was established on 21 June 1974 as the Coordinating Committee of the Armed Forces, Police and Territorial Army, by junior and mid level officers of the Imperial Ethiopian Army and members of the police. The officers decided everything collectively at first, and selected Mengistu Haile Mariam to chair the proceedings. On 12 September 1974, the Derg overthrew the government of the Ethiopian Empire and Emperor Haile Selassie during nationwide mass protests, and three days later formally renamed itself the Provisional Military Administrative Council. In March 1975 the Derg abolished the monarchy and established Ethiopia as a socialist state under a military-led provisional government. The abolition of feudalism, increased literacy, nationalization, and sweeping land reform including the resettlement and villagization from the Ethiopian Highlands became priorities. Mengistu became chairman in 1977, launching the Red Terror (Qey Shibir) political repression campaign to eliminate political opponents, with tens of thousands imprisoned and executed without trial.

The First Italo-Ethiopian War, also referred to as the First Italo-Abyssinian War, or simply known as the Abyssinian War in Italy (Italian: Guerra d'Abissinia), was a military confrontation fought between Italy and Ethiopia from 1895 to 1896. It originated from the disputed Treaty of Wuchale, which the Italians claimed turned Ethiopia into an Italian protectorate, while the Ethiopians claimed that the treaty simply ensured peace between the two powers. Full-scale war broke out in 1895, with Italian troops from Italian Eritrea achieving initial successes against Tigrayan warlords at Coatit, Senafe and Debra Ailà, until they were reinforced by a large Ethiopian army led by Emperor Menelik II. The Italian defeat came about after the Battle of Adwa, where the Ethiopian army dealt the Italian soldiers and Eritrean askaris a decisive blow and forced their retreat back into Eritrea. The war concluded with the Treaty of Addis Ababa. Because this was one of the first decisive victories by African forces over a European colonial power, this war became a preeminent symbol of pan-Africanism and secured Ethiopia's sovereignty until the Second Italo-Ethiopian War of 1935–37.

Gugsa Welle (1875 – 31 March 1930; as spelled as Gugsa Wale or Gugsa Wolie, and cited as Ras Gugsà Oliè in Italian books and encyclopedias), was an Ethiopian army commander and a member of the imperial family of the Ethiopian Empire. He represented a provincial ruling elite which was often at odds with the Ethiopian central government.