Generally, a battle is a specific instance of combat in warfare between two or more parties wherein each group will seek to defeat the others. Battles are most often fought during wars or military campaigns and can usually be well defined in time, space and action. Wars and military campaigns are guided by strategy whereas battles are the stage on which tactics are employed. German strategist Carl von Clausewitz stated that "the employment of battles to gain the end of war" was the essence of strategy. by William Sadler]] Characteristics of battle British military historian Sir John Keegan suggested an ideal definition of battle as "something which happens between two armies leading to the moral then physical disintegration of one or the other of them" though the origins and outcomes of battles can rarely be summarized so neatly. The "action" of battle is to reach a decision; the ideal decision is