World War II was a global military conflict lasting from 1939 to 1945, which involved most of the world's nations, including all of the great powers: eventually forming two opposing military alliances, the Allies and the Axis. It was the most widespread and deadliest conflict in human history, resulting in 50 million to over 70 million fatalities.
On the day of Japan's attack on Pearl Harbor, Michael Corleone volunteered for the Marine Corps against his father's wishes. Michael was sent to fight in the Pacific and took part in the battles of Guadalcanal and Peleliu. For his bravery in battle, Michael was awarded the Navy Cross and was also featured in Life Magazine. When Michael Corleone was discharged in early 1945 to recover from a disabling wound, he had no idea that his father had arranged his release.
Michael's caporegime, Rocco Lampone, also participated in World War II. He had been wounded in North Africa and was discharged in 1943. Rocco was awarded the Purple Heart, but he was partially incapacitated by his injuries and walked with a pronounced limp ever since.
The liberation of Sicily
During the war, the Mafia members not banished to Ustica by the Fascists had functioned in Sicily as the Resistance. They provided the American army with intelligence and helped them during their invasion of Sicily in 1943.
The British, who did not collaborate with the Mafia, suffered heavy casualties in their battles to take the eastern third of the island, but on the western two thirds, particularly in the regions that were Mafia strongholds, the Americans profited from superior intelligence and sustained relatively few casualties.
After the invasion, in many of the cities occupied by the Americans, the civilians installed as provisional mayors were mafiosi. When the Allies withdrew, most of the mayors stayed. And when the Dons were freed from Ustica, they returned home to find that the political power of the Mafia had increased exponentially.