Dennis Hart Mahan (Mă-hăn) [məˈhæn] (April 2, 1802 – September 16, 1871) was a noted American military theorist, civil engineer and professor at the United States Military Academy at West Point from 1824–1871. He was the father of American naval historian and theorist Rear Admiral Alfred Thayer Mahan. A native of New York City, Mahan was raised and educated in Norfolk, Virginia. He was an 1824 graduate of the United States Military Academy; ranked first in class, Mahan's high academic standing earned him appointment to the United States Army Corps of Engineers. Mahan's mathematical and engineering skills were recognized by his instructors and the superintendent, Sylvanus Thayer, and he began teaching courses as an acting assistant professor during his third year as a student. Mahan received advanced training in engineering during an extended trip to Europe, including attendance at the French engineer and artillery school in Metz. He resigned his commission in 1832 to become chairman of West Point's Engineering Department, and he remained on the faculty until his death. Mahan taught many of the military leaders who served on each side during the American Civil War, and his extensive writings on military engineering, fortifications, and strategy became required reading among military professionals through World War I. In 1871, West Point's board of overseers recommended that he be retired because he was in ill health. On September 16, 1871, Mahan was aboard a Hudson River steamboat on his way to New York City to visit his doctor when he became distraught over the thought of retiring and committed suicide by jumping into the boat's paddlewheel. Mahan was buried at West Point Cemetery. Early life Mahan was born in New York City on April 2, 1802, the son of Irish Catholic immigrants John Mahan and Mary (Cleary) Mahan. He was raised and educated in Norfolk, Virginia, and in 1820 received an appointment to the United States Military Academy from U.S. Representative Thomas Newton Jr. Mahan graduated in 1824, first in his class. His academic acumen was recognized while he was still a student, and in his third year at West Point superintendent Sylvanus Thayer appointed him acting assistant professor of mathematics. After graduation, he continued to serve on the faculty. Start of career In 1826, Mahan went to Europe to study advanced engineering, and from 1829 to 1830 he was a student at France's school of engineers and artillery in Metz.