![](https://www.historynet.com/wp-content/uploads/2022/02/CWTP-220200-ANTIETAM-01-4c-scaled.jpeg)
Brigadier General John Gibbon’s 4th Brigade in Abner Doubleday’s 1st Corps—the famed “Iron Brigade”—advances near the Dunker Church during Antietam’s early-morning fighting, in an 1887 chromolithograph by Thure de Thulstrup. (Library of Congress)
Library of Congress