Siege of Saïo the Italian dictator, Benito Mussolini, proclaimed the colony of "Africa Orientale Italiana" (AOI, Italian East Africa), formed from Ethiopia (after the Italian victory in the Second Italo-Ethiopian War, fought 3 October 1935 – May 1936) and the existing Italian possessions of Italian Eritrea and Italian Somaliland. On 10 June 1940, Mussolini declared war on Britain and France, which made Italian military forces in Libya a threat to Egypt and those in Italian East Africa a danger to the British and French colonies in East Africa. Italian belligerence also closed the Mediterranean to Allied merchant ships and endangered British supply routes
Italian East Africa in 1936, Italian East Africa (the other Italian colony in Africa being Italian North Africa) consisted of the old Italian possessions in the Horn of Africa, Italian Eritrea and Italian Somaliland, and the recently annexed Empire of Ethiopia. Victor Emmanuel III of Italy consequently adopted the title of "Emperor of Ethiopia", although having not been recognized by any country other than Nazi Germany and Imperial Japan. The territory was divided into the six governorates of Italian East Africa: Italian Eritrea and Italian Somaliland, plus four provinces of Ethiopia (Amhara, Galla-Sidamo, Scioa, Harar) each under the authority of an Italian governor,