Von Bülow, the author of _The Spirit of Modern Warfare_ (1798)[5], calls those movements strategical which are made outside the enemy’s sphere of information. Von Willisen considers strategy the science of communications, tactics the science of fighting. Von Clausewitz calls strategy the science of the use of battles for the purpose of the war (Jomini: “_l’art de diriger les armées sur les théatres d’opérations_”)[6], tactics the science of the use of military forces in battle (Jomini: “_l’art de diriger les troupes sur les champs de bataille_”).[7][8] General von Horsetzki (1892) defines strategy as the study of the conditions necessary for success in war. Archduke Charles calls strategy the “science of war” and tactics the “art of war”. Frederick the Great and Napoleon always employed the term “_l’art de guerre_” instead of the term “_strategy_”. None of these definitions are comprehensive enough, because they do not cover marches, outposts, the supply service, and enterprises in minor tactics. Professor Delbrück’s definition is much more appropriate: “Strategy is the science of utilizing military resources for the attainment of the object of the war, tactics the art of leading troops into and in battle.” Thiers, the French historian, instead of seeking to define strategy and tactics, contents himself with explaining the problems of each: “_Le stratège doit concevoir le plan de campagne, embrasser d’un seul coup d’oeil tout le théatre présumé de la guerre, tracer lignes d’opérations et diriger les masses sur les points décisifs. Le tacticien a pour mission de régler l’ordre de leurs marches, de les disposer en bataille aux différents points, indiqués par le stratège, d’engager l’action, de la soutenir et de manoeuvrer pour atteindre le but proposé._”[9] Fieldmarshal Moltke calls strategy “the application of common sense to the conduct of war.”[10] For practical purposes it is sufficient to define strategy as the _science of the conduct of war_, tactics as the _science of troop-leading_. Strategy brings about the decision on the theater of war, while the duty of carrying it out, in the manner desired by the commander-in-chief, devolves upon tactics. Thus the strategical idea culminates on the battlefield. The concentric advance of the Prussian armies into Bohemia in 1866 naturally led to a complete envelopment of the Austrians on the field of Königgrätz. The German attack in the battle on the Hallue, Dec. 23rd, 1870, was based on the strategical requirement of driving the French from their line of retreat leading to Arras and Bapaume, by enveloping their right flank. The attempts made by the 15th Infantry Division, which was holding the enemy in front, to envelop the left wing of the French, interfered with the execution of the correct strategical plan. Thus, in following up a success, in itself quite unimportant (the capture of Bussy), the leading basic principle was forgotten. The same thing happened here