As a result of their defeat in World War I and the resulting Treaty of Versailles, Germany lost Alsace-Lorraine, Northern Schleswig, and Memel. The Saarland became a protectorate of France under the condition that its residents would later decide by referendum which country to join, and Poland became a separate nation and was given access to the sea by the creation of the Polish Corridor, which separated Prussia from the rest of Germany, while Danzig was made a free city.[163]