@Prince of Lasanod
Contrary to popular opinion, colonization of Ethiopia was not the intention of the Italians. It may have been the result if they won the battle, but initially, the war they fought was to settle a treaty dispute they had with Emperor Menelik II. On April 1889, Menelik signed the Treaty of Wuchali with the Italians. In return for financial assistance and modern weaponry, Italy was given the northern provinces of Eritrea and Tigray. This was a cunning political move by Menelik, because Tigray was the native province of his chief rival Mengesha Yohannes, the previous emperor's son. By placing Tigray under Italian control, Menelik deprived Yohannes of valuable local support.
There was however, one clause of the treaty which both sides had differing interpretations. According to the Italian version, Article 17 states that the Ethiopian emperor is
obligated to go through Italian channels for diplomatic representation. In other words, the Emperor
must ask for permission and aid when speaking to foreign states. This clause would in practice make Ethiopia a protectorate of the Italian state. This was a common tactic used by European powers when signing treaties with local rulers. Subtle interpretations would state that the local rulers had effectively
submitted to European control, and the if the local rulers disputed this (which they often did), the Europeans would justify military action by claiming treaty violation.
The Amharic version on the other hand, stated that the Emperor was
not obligated to rely upon Italian diplomacy. He could if he wished to, but it was by
no means mandatory. The Italians claimed that the Emperor signed the treaty with the awareness of this obligation but later changed it on his own accord. Historians continue to debate today whether it was a case of simple misinterpretation or that one side deliberately changed their versions after the signing. Neither the Italian colonizers or the machiavellian Menelik were saints, so both sides are valid culprits. But we will probably never know.
But in any case, both sides demanded the other correct the interpretation, but neither would budge, even after an attempt to buy off Menelik. Italy came to the decision that a military solution was the most efficient way to teach the 'barbarians' a lesson.
Initially, the Italians were successful in crushing an Ethiopian-supported insurgency in Eritrea (December 1894) and defeating Mengesha Yohannes (the previous Emperor's son) at Coatit (January 1895). The Ethiopians later defeated the Italians at Amba Alagi (December 1895) and Mek'ele (January 1896).
This forced the Italians into a retreat through the mountainous area of Adwa, where the Italians were dangerously short on manpower. The Italian commander Oreste Baratieri wanted to focus on defense, because unlike his army which relied upon supply lines, the Ethiopian army lived off the land, and would melt away once the local peasants were exhausted.
But to his detriment, the Italian government was impatient and eager for a PR victory. They ordered Baratieri to attack with fewer numbers. The politicians simply could not accept the shameful eventuality of fleeing from an 'inferior' race. One of Baratieri's brigadiers stated:
"Italy would prefer the loss of two or three thousand men to a dishonorable retreat."
In the end, Baratieri reluctantly set a date for an attack. On March 1st, 1896, the 20,000-strong Italian army was to attack an Ethiopian force between 73,000 to 120,000 men.
The combat effectiveness of the Italians has been exaggerated, a few thousand of the 20,000 were most likely support personnel, thereby reducing the actual combat effective strength to about 15,000, divided into four brigades.