Napoleonic military theory changed military minds in the Western world in the late 19th century. Dennis Hart Mahan, who was in the United States army, was developed Napoleonic military art in his "Elementary Treatise on Advanced Guard, Outposts, and Detachment Service of Troops" and taught it in military school. Alfred Thayer Mahan, his son, wrote "The Influence of Sea Power Upon History, 1660–1783" and became a naval strategist based on the military theory of Jomini and Clausewitz. In the Prussian army, Helmunth von Moltke lead studies of military theory, and made ideas of "Auftragstaktik" (mission tactics). By Moltke's study, Prussia got theories on how to move forces faster in the field and showed evidence of this theory through victory in the Franco-Prussian War. Alfred von Schlieffen, Prussian general and military theorist, made the plan of a two-front war against France and Russia, using fast strategic movement. In France, Charles J. J. J. Ardant du Picq developed military theory in his "Battle Studies" from the point of mental part of war. Ardnt du Picq thought military action is related to mental situations of military force.