The assault on Vimy Ridge, the northern part of the wider battle of Arras, began at 5:30 am on Easter Monday, April 9, 1917.It was the first occasion on which all four divisions of the Canadian Corps attacked as a composite formation. The Canadian achievement in capturing Vimy Ridge owed its success to a range of technical and tactical innovations, very powerful artillery preparation, sound and meticulous planning and thorough preparation.At Vimy, the Canadian Corps and the British XVII Corps on their immediate southern flank had captured more ground, more prisoners and more guns than any previous British Expeditionary Force offensive. Vimy Ridge was a particularly important tactical feature. Its capture by the Canadians was essential to the advances by the British Third Army to the south and of exceptional importance to checking the German attacks in the area in 1918.The Canadians had demonstrated they were one of the outstanding formations on the Western Front and masters of offensive warfare.Four Victoria Crosses (VC) were awarded for bravery. Of these, three were earned on the opening day of the battle: