Along with Neville Chamberlain, Benito Mussolini and Adolf Hitler, Daladier signed the Munich Agreement in 1938, which gave Nazi Germany control over the Sudetenland. After Hitler's invasion of Poland in 1939, Britain and France declared war on Germany. During the Phoney War, France's failure to aid Finland against the Soviet Union's invasion during the Winter War led to Daladier's resignation on 21 March 1940 and his replacement by Paul Reynaud. Daladier remained Minister of Defence until 19 May, when Reynaud took over the portfolio personally after the French defeat at Sedan.