A Union army officer, diplomat and best-selling author, Lewis Wallace joined the Union army as colonel of the 11th Indiana Infantry in April 1861. Wallace initially served with his unit in the Department of Western Virginia. After advancing to the rank of brigadier general in September 1861, he played a key role in the capture of Fort Donelson. Wallace was promoted to major general in March 1862. In command of a reserve division under Grant at the Battle of Shiloh, he may have misinterpreted Grant's orders to move his division up in support of Gen. Sherman's troops at Shiloh Church. By the time Wallace's division arrived on the scene, the fighting had virtually ceased for the day. Although, Union forces carried the battle the next day, the casualty toll was horrific. Wallace received the lion's share of the blame from his superiors and was eventually reassigned to a regimental command protecting the city of Cincinnati during Kirby Smith's invasion of Kentucky.
Wallace's greatest battlefield contribution may have been in the defense of Washington, when he cobbled together a force of 5,800 men and checked the advance of Gen. Jubal Early's 15,000-man Confederate army at the Battle of Monocacy on July 9, 1864. In 1865 he served on the military tribunal that tried those charged with the assassination of President Abraham Lincoln. Later that year, Wallace presided over the military tribunal that condemned Confederate Major Henry Wirz, commandant of the notorious Andersonville prison camp.
After the war, Wallace served as governor of the New Mexico Territory from 1878 to 1881. In 1881 he accepted an appointment as U.S. Minister to the Ottoman Empire, serving until 1885. Today, Wallace is perhaps best remembered as a novelist, especially for his work Ben-Hur: A Tale of the Christ, which became a stage play and a major motion picture and is to this day the best selling American novel fo all time (from the date of its publication).