Upon returning to West Point in 1830, he was promoted to professor of civil and military Engineering. He resigned his second lieutenant's commission in 1832 to become chairman of West Point's Engineering Department, and he remained on the faculty until his death. Mahan was subsequently appointed dean of the faculty and became a recognized authority on engineering. In addition to becoming a member of several scientific and professional societies, he also carried out special appointments that took advantage of his technical skills. In 1828, he was elected to membership in France's Société de Géographie. In 1850, Governor John B. Floyd of Virginia appointed Mahan to the board that recommended a route for the Baltimore and Ohio Railroad to run from Cumberland, Maryland to a terminus in Wheeling, West Virginia, which was then part of Virginia. In 1863, Mahan was an original incorporator of the National Academy of Sciences. In 1871, he was appointed to the board of overseers for the Thayer School of Engineering at Dartmouth College. Mahan founded the Napoleon Club at West Point. In the club's seminars, which reviewed the engagements of the Napoleonic Wars, advanced undergraduates studied and discussed the great European battles, including the campaigns of Napoleon and Frederick the Great. Participants included Robert E. Lee, John F. Reynolds, George Henry Thomas and George B. McClellan. As an author, Mahan promoted military professionalism and wrote extensively on strategy and tactics, fixed fortifications, and field fortifications. His writings became standard textbooks for the armies of several countries, and remained required reading from the time they were written until after World War II. Continued career Mahan was largely responsible for disseminating ideas of European military theorists throughout the United States, particularly Antoine-Henri Jomini, and his lectures and writings were instrumental to U.S. actions in every conflict from the Mexican–American War and American Civil War to World War I and World War II. A proponent of a disciplined professional army in an era when the United States relied on a small standing army augmented with minimally trained volunteers and militia, Mahan strongly advocated providing discipline and training for militia and volunteers as a means of improving their performance on the battlefield. The theories Mahan advocated included the use of combined arms to defeat an enemy, rather than relying on infantry with the other arms only in support. In his writings, Mahan emphasized the use of artillery, infantry, and cavalry