418. The Color-Sergeant—In each regiment a sergeant is selected for his gallantry and military bearing, to carry the regimental colors. He is accompanied by a color-guard, composed of five corporals, who are also distinguished for their military conduct. They parade the colors on all occasions when the regiment is formed for the march, parade, review, or for battle. The sergeant is in the front rank, the two senior corporals are on the right and left of the sergeant, and the three junior corporals are in the rear rank. The post of the color-guard is on the left of the right centre company. All the romance and heroism of the regiment centre in the color-guard and the emblem with which they are interested. On it are inscribed the battles in which the regiment has participated. Much depends upon the courage and daring of the color-sergeant. Wherever he will carry the flag, the men will follow to protect and defend it; and no commissioned officer occupies a post that is so likely to bring distinction and promotion if he does his duty; whilst none is more certain to bring disgrace if he proves recreant in his trust.

Customs of the Service [US Army - 1864]
August V. Kautz