DENNIS MAHAN Biographies Pierre Beauregard Ambrose Burnside Joshua Chamberlain Decatur Dorsey John Gordon U.S. Grant Wade Hampton Winfield Hancock John Hartranft Henry Heth A.P. Hill Rufus Ingalls Bushrod Johnson Robert E. Lee William Mahone George Pickett Philip Sheridan William Smith Gouverneur Warren Medical Civilians PNB Home

Dennis Mahan Born in 1802 in New York, Dennis Mahan graduated from West Point in 1824. He started teaching at the academy soon after and was sent to Europe to study. In 1830 he was promoted to professor of civil and military engineering. As a teacher of military science, Mahan promoted defensive tactics on the battlefield. From him most of those who became Civil War commanders, be it Union or Confederate, learned about entrenchment and fortifications, and how to conduct siege warfare. Nowhere was his influence greater in the Civil War than at the Siege of Petersburg. While his theories affected the lives of the nearly 200,000 men in the trenches around Petersburg and Richmond