On 22 May 1939, Germany and Italy signed the Pact of Friendship and Alliance that became known later as the Pact of Steel. This began the formal military and political alliance between the two countries. Initially Japan was to be part of the agreement but there was disagreement on the focus of the pact. Germany and Italy wanted it aimed at the British Empire and France, while Japan wanted the Soviet Union to be the focus. The agreement was signed without Japan but would later join in September 1940.

The agreement brought together two countries that opposed each other in World War I. It also required each country to come to the aid of the other if it were in armed conflict with another nation. Neither party could make peace without the agreement of the other. One of the assumptions of the agreement was that war would start in three years at the latest. Italy needed the time to get its war production into high gear. The agreement was for ten years but there was some concern within the Italian government the agreement would suppress Italian autonomy. The agreement was still signed despite these objections, which also came from Mussolini’s son-in-law, Galeazzo Ciano, who was the Minister of Foreign Affairs.

Hitler, however, would soon declare his intentions of invading Poland. Mussolini was not happy he was not consulted on this, nor about the Molotov-Ribbentrop Agreement. Italian forces did not commit fully to war until June 1940 when German forces had defeated British and French forces with lightning speed. Italy seized Nice as its prize. Other countries it tried to invade proved more difficult. Greek partisans brought the Italian force to a halt. Germany would intervene to help there and in Yugoslavia where Italian troops also pushed back by partisans. A disastrous attack on British Egypt from Italian Libya required German assistance as well. The economic consequences of the war were bad for most Italians generating widespread resentment that would lead one day to Mussolini’s fall from power in 1943.

Sources:

History.com
School History
World War II Database