The New Dictionary of Cultural Literacy, Third Edition. 2002.
Jackson, Stonewall
Thomas J. Jackson, a general in the Confederate army during the Civil War. He got his nickname at the First Battle of Bull Run, where he and his men stood like a stone wall. He and General Robert E. Lee led the South to victory at the Battle of Chancellorsville. In the evening after the battle was won, however, Jackson was fatally shot by Confederate troops who mistook him and his staff for Union officers.
In the poem Barbara Frietchie, by John Greenleaf Whittier, Stonewall Jackson orders his men not to harm Barbara Frietchie or the Union flags she is holding (seeShoot, if you must, this old gray head).