On what date did the German offensive of which the First Battle of Villers-Bretonneux was a part begin?
Spring Offensive The 1918 Spring Offensive or Kaiserschlacht ("Kaiser's Battle"), also known as the Ludendorff Offensive, was a series of German attacks along the Western Front during the First World War, beginning on 21 March 1918, which marked the deepest advances by either side since 1914. The Germans had realised that their only remaining chance of victory was to defeat the Allies before the overwhelming human and matériel resources of the United States could be fully deployed. They also had the temporary advantage in numbers afforded by the nearly 50 divisions freed by the Russian surrender (the Treaty of Brest-Litovsk).
Plan XVII Plan XVII (] ) was the name of a "scheme of mobilization and concentration" that was adopted by the French "Conseil Supérieur de la Guerre" (the peacetime title of the French General Staff) from 1912–1914, to be put into effect by the French Army in the event of war between France and Germany. Though it was not "a prescribed narrative for the campaign" or battle plan, the deployment made possible a prompt invasion of Germany and/or Belgium before Germany could mobilise its reserves, simultaneous to a Russian invasion of East Prussia. The plan was implemented from 7 August 1914, with disastrous consequences for the French, who were defeated in the Battle of the Frontiers (7 August – 13 September) at a cost of 329,000 casualties. The French northern armies were forced into a retreat as far as the Marne river, where in the First Battle of the Marne (5–12 September), the German armies were defeated and forced back to the Aisne river.