Operation Avalanche and the Italian mainland. The Allied invasion of Sicily in July 1943, codenamed Operation Husky, was highly successful, although many of the Axis forces there were allowed to avoid capture and escape to the mainland. More importantly a "coup" deposed Benito Mussolini as head of the Italian government, which then began approaching the Allies to make peace. It was believed a quick invasion of Italy might hasten an Italian surrender and produce quick military victories over the German troops that would now be trapped fighting in a hostile country. However, Italian (and more so German) resistance proved relatively strong, and
Allied invasion of Italy the U.S. Army Chief of Staff, General George Marshall, and much of the American staff wanted to avoid operations that might delay an invasion of Europe, which had been discussed and planned as early as 1942, and which finally materialized as Operation Overlord in 1944. When it became clear that no cross-channel invasion of occupied France could be undertaken in 1943, it was agreed to invade Sicily, with no commitment made to any follow-up operations. However, both Churchill and Franklin D. Roosevelt, the U.S. President, accepted the necessity of Allied armies continuing to engage the Axis in the period after