In August 1914, the European powers had gone to war with rudimentary air services and embryonic aviation industries. Once airplanes proved themselves as a means of reconnaissance and, most importantly, of artillery spotting, air commanders required more of them to conduct effective aerial operations and prevent enemy aerial reconnaissance. The second aim led to armed aircraft and then the development of specialised pursuit, or fighter, aircraft. The battles of Verdun and the Somme forced the codification of aerial combat tactics and brought home the importance of mass. Military aviation did not determine the outcome of the First World War, but the airplane did establish its very real significance in support of the army and especially the artillery on the battlefield. Theory and wishful thinking after the Great War focused on strategic aviation and nearly drove the lessons of tactical aerial importance and success from the minds of post-war observers.