Arthur Neville Chamberlain was a British politician who served as Prime Minister of the United Kingdom from May 1937 to May 1940 and Leader of the Conservative Party from May 1937 to October 1940. He is best known for his foreign policy of appeasement, and in particular for his signing of the Munich Agreement on 30 September 1938, ceding the German-speaking Sudetenland region of Czechoslovakia to Nazi Germany led by Adolf Hitler. Following the invasion of Poland on 1 September 1939, which marked the beginning of the Second World War, Chamberlain announced the declaration of war on Germany two days later and led the United Kingdom through the first eight months of the war until his resignation as prime minister on 10 May 1940.