Plans to exploit the Franco-British superiority in numbers on the Western Front, while one third of the German army was on the Russian Front were agreed at a Conference by Joffre and French at Chantilly on 14 September. The British New Armies had begun to arrive, the number of heavy guns had increased since the offensives of May and June and by concentrating resources at the points of attack an even greater numerical superiority could be obtained over the Germans. An unprecedented preliminary bombardment of the German defences would be possible and make attacks by the greater number of Allied infantry decisive. Simultaneous offensives would be mounted from Champagne and Artois towards Namur, the principal attack being made in Champagne.