The Iron Brigade A Military History Author:Alan T. Nolan This is the story of the most famous unit in the Union Army, the only all-Western brigade in the Eastern armies of the Union. Originally called the "Black Hat Brigade" because soldiers wore the regular dress black hat instead of the blue cap, this brigade fought at Bull Run, South Mountain, Antietam, Fredericksburg, Chancellorsville, and Gettys... more »burg.« less