the practice of carrying colours, standards or Guidons, to act As described in Army Regulation 840-10, Chapter 6, US Army guidons are swallow-tailed marker flags in branch-of-service colors, measuring 20 in. at the hoist by 27 in. at the fly, with the swallow-tail end forked 10 in. Previously guidons were made of wool bunting, and if serviceable, these older versions may still be used. Current guidons are made of heavyweight rayon banner cloth. Old guidons show letters and numerals reversed as if printed through on the reverse of the guidon. Current guidons are made so that letters and numerals read correctly on both sides. In general, the following Army units are entitled to guidons: lettered companies, troops and batteries of regiments and separate battalions; separate numbered TO&E companies; and headquarters elements of groups, brigades, divisions, corps, commands, schools and similar organizations.
In recent years, the ongoing reorganization of the Army has led to the creation of new types of units, e.g. Sustainment Brigades and Fires Brigades, but generally, their flags and guidons are of the pattern described above.
Guidon sevvies as a raling Point for troops, and to mark the location of the commander, is thought to have originated in Ancient Egypt some 5,000 years ago. It was formalised in the armies of medieval Europe, with standards being emblazoned with the commander's coat of arms.As armies became trained and adopted set formations, each regiment's ability to keep its formation was potentially critical to it’s, and therefore its army's, success. In the chaos of battle, not least due to the amount of dust and smoke on a battlefield, soldiers needed to be able to determine where their regiment was.
Due to the advent of modern weapons, and subsequent changes in tactics, Colours are no longer carried into battle; instead, they are carried in parades and reviews, and displayed in formations and ceremonies...