The Allied invasion of Italy was the Allied amphibious landing on mainland Italy that took place from 3 September 1943, during the Italian campaign of World War II. The operation was undertaken by General Sir Harold Alexander's 15th Army Group and followed the successful Allied invasion of Sicily. A preliminary landing in Calabria took place on 3 September, the main invasion force landed on the west coast of Italy at Salerno on 9 September as part of Operation Avalanche at the same time as a supporting operation at Taranto.