 The 6th Army then retreated to the Oppy–Méricourt line.Historians attribute the success of the Canadian Corps to technical and tactical innovation, meticulous planning, powerful artillery support and extensive training, as well as the inability of the 6th Army to properly apply the new German defensive doctrine.The battle was the first occasion when the four divisions of the Canadian Expeditionary Force fought together and it was made a symbol of Canadian national achievement and sacrifice.