During the Greco-Italian war, the Kingdom of Italy attacked Greece with the purpose of annexing part of Greek territory. The Italians invaded Greece through Albania, which had been previously annexed by Italy, but the invasion turned out to be a disaster for the Italians. The Greeks counterattacked and pushed the Italian army back into Albania. After another failed Italian offensive in the spring, Adolf Hitler decided to come to his ally’s aid. Germany attacked northern Greece, and so the Greeks made a belated withdrawal from Albania, to avoid being cut off by the Germans.
The Italians foresaw a two-stage campaign. First, their forces in Albania (a country that Mussolini had seized in April 1939) would drive south and occupy northern Greece, as their navy seized the most important Aegean islands. Then the troops would continue the march south to Athens for a final assault. Heavy bombing to terrorize Greek civilians would help precipitate the fall of the regime.
The Greeks had picked up indications that an invasion was coming, and the Greek ambassador in Rome warned his government to expect an invasion. Thus alerted, the Greeks mobilized. Their forces along the frontier were quite similar in size and composition to the Italians’, but Greek artillery was better.
When Hitler and Mussolini had met on the Brenner Pass, the Führer did not warn the Duce that he intended to occupy Romania only three days later. Similarly, Mussolini’s invasion of Greece, under General Sebastiano Visconti Prasca, was undertaken from occupied Albania with ten divisions without Hitler’s prior knowledge. With temperatures of -20° Celsius, difficult territory and stiff Greek resistance under General Alexander Papagos, the Italians were soon forced back into Albania.
A Greek counter-offensive began and quickly threw the Italian forces back into Albania. The front then stabilized approximately thirty miles inside Albania with Italian counter-offensives held by the Greeks, and further Greek attacks making only smaller advances; both sides were exhausted.
The humiliating setbacks suffered by Italy's armed forces against the Greeks, accompanied by the Tarante raid, and soon followed by the collapse in North Africa, shook the Fascist system in Italy. Here were unmistakable signs of incompetence on the one hand and a war obviously about to last a long time on the other. If anyone in Italy had doubts on either score, they were enlightened by the remobilization that was now ordered, by a dramatic tightening of the rationing of basic foodstuffs, and by the British naval bombardment of Genoa.
By the end of January the Italians had succeeded in stemming the Greek advance. By February they were strong enough to counterattack, though with disappointing results; the Greeks hardly budged despite attacks that led to extraordinarily high casualties among Italian units.
The Italian Spring Offensive was the last attempt to win the war against Greece without German support. The offensive opened under the supervision of Mussolini, but ended up being a failure.
The Italians, who had earlier proudly refused German help, were forced by their defeat to ask for help. The decision to intervene in the Balkans confronted the Germans with the logistic and diplomatic difficulties of committing major forces to southern Europe. Winter weather exacerbated the difficulties.