On what date did the German offensive of which the First Battle of Villers-Bretonneux was a part begin?
First Battle of Villers-Bretonneux: The First Battle of Villers-Bretonneux (30 March – 5 April 1918), took place during Operation Michael, part of the German Spring Offensive on the Western Front. 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.
21 March 1918