However, subsequent conflicts would largely discredit Douhet's theory. Air Marshal Arthur "Bomber" Harris set out in 1942 to prove Douhet's theories valid during World War II. Through four years under his command, RAF Bomber Command attempted to destroy the main German cities. By 1944–1945, in partial concert with the USAAF, they had largely achieved this aim; but no revolution toppled the Third Reich. The heavy bombers involved in the Combined Bomber Offensive did not win the war alone, as Harris had argued they would. Douhet's theories about forcing the population to start a revolution, when subjected to practical application, were shown to be ineffective. In fact, there is considerable evidence to show the bombings did nothing but antagonize the German people, galvanizing them to work harder for their country, and the final defeat of Germany was not achieved until virtually the entire country had been occupied by Allied land forces.