The second battle of Artois, 9 May-18 June 1915, was the most important part of the Allied spring offensive of 1915. It was hoped to capture Vimy Ridge, break through the German lines, and advance into the Douai plain. This would cut key German railway lines and perhaps force them to retreat from their great salient bulging out into France.
The Allied offensive was pre-empted by the German gas attack at Ypres (second battle of Ypres, 22 April-25 May 1915). By the time the Artois offensive began, the real crisis at Ypres had passed, but it did prevent the BEF from playing a bigger part in the planned offensives. Even so, the British First Army, under General Haig, was allocated to the offensive, and was to attack Aubers Ridge, over the same ground attacked during the battle of Neuve Chapelle (10-13 March 1915).
The French offensive would be launched by the Tenth Army, under General d’Urbal. It was supported by 1,200 guns with 200,000 shells, a huge amount for ammunition for 1915 (later bombardments would use millions of shells). The artillery bombardment began six days before the attack was due to go in.
The British attack at Aubers Ridge was a total failure. It cost the BEF 10,000 casualties and achieved nothing. In contrast, the French attack on 9 May opened with a dramatic success. Pétain’s XXXIII corps advanced 2.5 miles in the first hour and a half of the battle, and the 77th and Moroccan Divisions actually reached the crest of Vimy Ridge.
General d’Urbal had not expected such rapid successes, and his reserves were six miles behind the front line, preparing to move up over the next few days. The German reserves were much better placed, and by the end of the day the French had been pushed back off the top of the ridge.
Over the next five weeks the French and Germans engaged in a battle of attrition in the area immediately behind the old German front line. This was a maze of communications trenches and strong points, where progress was slow and costly. The Moroccan Division did manage to fight its way back onto Vimy Ridge on 16 June, but was once again pushed back. A second British attack, at Festubert, 15-27 May 1915, was less disastrous than the attack at Aubers, but also marked a change to a war of attrition.
The attack in Artois failed to achieve its original objectives. Vimy Ridge remained in German hands until it fell to the Canadians in 1917 (Battle of Vimy Ridge), while the battle of attrition favoured the Germans. The French suffered 100,000 casualties, the Germans 75,000, and as the French were well aware there were more Germans than Frenchmen.
The fighting in Artois would be renewed in the autumn of 1915 (Third battle of Artois), this time as part of a wider offensive that including the second battle of Champagne and the British failure at Loos.