The Prussian Army was composed not of regulars but conscripts. Service was compulsory for all of men of military age, and thus Prussia and its North and South German allies could mobilise and field some 1,000,000 soldiers in time of war. German tactics emphasised encirclement battles like Cannae and using artillery offensively whenever possible. Rather than advancing in a column or line formation, Prussian infantry moved in small groups that were harder to target by artillery or French defensive fire. The sheer number of soldiers available made encirclement en masse and destruction of French formations relatively easy.