Since the German annexation of French Alsace and Lorraine in 1871, France was determined to reclaim its lost territory. In 1913, responding to rising tension in Europe, they amended Plan XVII, originally drawn up in 1903. In the event of French-German conflict, the French planned to advance on Berlin after capturing Alsace and Lorraine. It was assumed by the French that German forces would be focusing on crossing neutral Belgium, to access France. On 20 August, the French implemented Plan XVII, advancing on German lines in Alsace and Lorraine. German machine guns and artillery fire halted the French, causing losses in the region of 200,000, growing to 454,000 by the end of November 1914. The French had sent four-fifths of their soldiers to attack the German positions in this region and the catastrophic loss of French lives is known as ‘the Battle of the Frontiers’.