The German attack on Vimy Ridge (Unternehmen Schleswig-Holstein/Operation Schleswig-Holstein) was a local attack on the Western Front on 21 May 1916, during the First World War. The Germans intended to prevent mines being blown under German positions by capturing the British front line and mine gallery entrances. After the Third Battle of Artois (25 September – 4 November 1915) the French Tenth Army had held positions on the western slope of Vimy Ridge and the German 6th Army occupied positions on the steeper eastern slope. During the Battle of Verdun (21 February – 18 December 1916), the Tenth Army was withdrawn and the British First Army and Third Army on either flank, took over the French positions.