With a long, diverse career as an illustrator, especially of Civil War subjects, Theodore Davis, known as Theo, is said to have "covered more areas of the fighting than any other artist." His work was highly detailed in documenting people and places, and much of it resulted from hurried notes he took during battles. He was wounded twice and had his horse shot out from under him.

In his Civil War reporting, he worked for Harper's, but traveled with William H. Russell, a neutral British journalist, and told people he was an artist for the Illustrated London News. This way, he also served as a spy for the North because he learned much about Southern weaponry. Sometimes he was in the center of the action, especially when he traveled with...