At the outbreak of the First World War, Alsace-Lorraine was a territory of Germany; Germany had acquired it from France during the Franco-Prussian War of 1870–71. While the area was mostly German-speaking (excepting the area around Metz), it had previously been part of France since the seventeenth century. France strongly resented this loss of territory; it did not view this loss as a permanent change to its borders and made plans to reconquer the territory. The fact that Germany treated Alsace-Lorraine more like a conquered territory than as an Imperial state didn't help matters much. At the start of the First World War, France attempted an invasion of Alsace-Lorraine, but was quickly repulsed. After the war, Alsace-Lorraine was assigned to France by the Treaty of Versailles.
