The Abyssinian War (more properly, the Second Italo-Abyssinian War)* lasted from October 1935 to March 1936. Fought between the fascist Kingdom of Italy and the Ethiopian Empire, the war's main significance was the brief creation of Italian East Africa and a further illustration of the weakness inherent in the League of Nations
At the beginning of the war, which was instigated by the Italians through the deliberate construction of a border fort in Ethiopian territory, the Italians had an overwhelming superiority in aircraft, artillery and tanks; the Ethiopians had very few of these items and most of what they did have was obsolete. The same is true of the regular forces. While on paper the Ethiopians had a larger army, most of it was armed with bows and spears. The Italians, in contrast, deployed twelve modern divisions, 400 airplanes, 500 tanks, and plenty of trucks to move their supplies. The Italians also had a large number of askaris, African troops led by Italian officers, and some tribal allies under their own leaders.
Predictably, the war was a one-sided slaughter, even before the Italians began to use chemical warfare. The Ethiopian Army did manage a victory during the Christmas Offensive, but losses were heavy. Britain and France did nothing to intervene for fear of losing Italy as an ally in the event of war with Nazi Germany, and eventually there was nothing left but for Emperor Haile Selassie to flee into exile.
At the end of the war, Italy had acquired a hugely expensive colony; improvements to roads and other infrastructure would cost 19 billion lire at a time when the entire revenue for the Italian Empire was only 18.5 billion lire. Resistance to the Italian occupation continued with diminishing effect until 1941, when the East African Campaign fanned it into new life. Italian East Africa fell to a combined force of British Commonwealth, Free Belgian, Free French, and Ethiopians in that year, although guerrilla fighting by Italians and their allies continued until Italy's surrender in 1943.
*The first Italo-Abyssinian War of 1895-96 was a humiliating defeat for the Italians.