Hitler took advantage of Britain and France's policy of appeasement to aggressively expand German territory. He first remilitarized the Rhineland, then supported Franco in the Spanish Civil War to test Germany's military. When Britain and France did nothing in response, Hitler grew bolder and annexed Austria to unite German-speaking peoples. After annexing the Sudetenland from Czechoslovakia at Munich, Hitler took the rest of the country. Confident that the Western allies would continue to appease him, Hitler then invaded Poland, prompting Britain and France's declaration of war and the start of World War II.