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).
Battle of Hartmannswillerkopf The Battle of Hartmannswillerkopf or "Hartmannsweilerkopf" (French: "bataille du Vieil-Armand" ) was a series of engagements during the First World War fought for the control of the "Hartmannswillerkopf" peak in Alsace in 1914 and 1915. Hartmannswillerkopf is a pyramidal rocky spur in the Vosges mountains, about 5 km north of Thann. The peak stands at 956 m and overlooks the Alsace Plain, Rhine valley and the Black Forest in Germany and was captured by the French army during the Battle of Mulhouse (7–10, 14–26 August 1914). From the vantage point, Mulhouse and the Mulhouse–Colmar railway could be seen and the French railway from Thann to Cernay and Belfort shielded from German observation.