In the early years of the Nazi regime, Neurath was regarded as playing a key role in the foreign policy pursuits of Hitler in undermining the Treaty of Versailles and territorial expansion in the prelude to World War II, although he was often averse to Hitler's aims tactically if not necessarily ideologically. This aversion eventually induced Hitler to replace Neurath in 1938 with the more compliant and fervent Nazi Joachim von Ribbentrop. Neurath served as Reich Protector of Bohemia and Moravia between 1939 and 1943, though his authority was only nominal after September 1941.