Alfred Thayer Mahan (1840-1914), American naval officer and historian, was born on September 27, 1840, in West Point, New York, to Dennis Hart (1802-1871), a United States Military Academy professor, and Mary Helen (Okill) Mahan. Mahan graduated second from his class at the United States Naval Academy in 1859 and went on to serve nearly forty years of active duty in the United States Navy. He rose to the rank of Lieutenant while fighting in the American Civil War (1861-1865), was named Captain in 1885, and retired from active service in November 1896. Thayer was promoted to the rank of Rear Admiral on June 29, 1906, by an act of Congress which promoted all retired captains who had served during the Civil War.

In October 1885, Mahan was invited by Stephen Luce (1827-1917), president of the newly established Naval War College in Newport, Rhode Island, to serve as a lecturer on naval history and tactics. Mahan was later appointed president of the Naval War College in June 1886 to January 1889 and again from July 1892 to May 1893. The lectures Mahan gave at the college became the basis for the Influence of sea power upon history, 1660-1783, published in 1890, the first of twenty books and twenty-three essays written by Mahan on this broad subject. Mahan’s works on naval history and strategies greatly influenced the buildup of naval forces among the major world powers in the years prior to World War I. Rear Admiral Alfred Thayer Mahan died on December 1, 1914, in Quogue, New York.