Nathaniel Lyon (July 14, 1818 – August 10, 1861) was the first Union general to be killed in the American Civil War and is noted for his actions in the state of Missouri at the beginning of the conflict. Some credit his quick action and hard line Unionism for stopping the Missouri secession movement. Others question his influence peddling and his role in events such as the Camp Jackson Affair, which inflamed many Missourians on the secession issue (See Missouri secession.)