Answer
Confederate General Thomas J. "Stonewall" Jackson was wounded by friendly fire on May 2, 1863, during the Battle of Chancellorsville. The wound became infected, and he died of pneumonia eight days later on May 10, 1863. Jackson's death was a major blow to the Confederate army, and his loss is often cited as one of the factors that led to the Union victory at Gettysburg a few weeks later.