corps badges in the american civil war were originally worn by soldiers of the union army on the top of their army forage cap, left side of the hat, or over their left chest pocket. the idea was suggested by major geneneral philip kearny. during a battle he reprimanded officers that turned out to not be under his command. to prevent that from happening again, he ordered the men in his division to sew a square of red cloth on their hats. this idea was adopted by major general joseph hooker after he assumed command of the army of the potomac. this was so any soldier could be identified at a distance.