By mid-1918, the character of the First World War had changed completely from the relatively static previous three years of battle. In March, the Germans had launched their desperate gamble to win the war in a single massive offensive and had been halted, at great cost to both sides, by June. On 18 July the French, aided by American forces, launched their highly successful counter-attack at Soissons and demonstrated that the German forces were far weaker t h a n the previous year. The opportunity was ripe to strike quickly and in force. This occurred at 4:20 a.m. on the 8th of August when the Battle of Amiens opened with the resounding crash of the combined artillery of two armies. One of the most powerful Allied forces ever assembled during the Great War, consisting of the French First (Debeney) and British Fourth (Rawlinson) Armies strengthened by the Canadian Corps and the entire British Cavalry and Tank Corps, rushed forward and fell upon the first line of generally ill-prepared and heavily outmatched Germans just east of the important railway centre at Amiens.