The British legacy: three colours
Tracing back the oldest ingredients of the confederate battle flag, one ends up in Scotland. Near Athelstaneford, in 832AD, an army of Scots and Picts defeated, against all odds, a much larger force of Angles. Legend has it that during the battle white clouds formed an X-shaped cross in the blue sky, and that's how St. Andrew, crucified on such a cross, became the patron saint of Scotland, and Scotland's flag became a white St. Andrew's cross on a blue field.
|British Union (flag), 1606-1801|
At sea, the Union was placed as a canton on an ensign with a red, white or blue field. In and around British America mostly the Red Ensign was seen. The three ensigns correspond to the three colours of the Union Flag. If so, the red in the Red Ensign is that of Saint Michael/George. The "canton with the Union" was also called "union" for short.
|British Red Ensign, 1620-1801|
December 2, 1775, an American rebel at sea altered the Red Ensign by adding six white stripes, creating thirteen stripes to represent the rebel colonies. On July 4, 1776, these Continental Colors became the common flag of the united colonies. (Cannon p. 26)
|Flag of the USA, 1776-1777|
The canton of the USA flag would be changed one year later, but the British colours were there to stay. The newborn Americans, proud of their achievement and their flag, thought of red-white-blue as the "liberty colors" (Preble p. 509), associated with "republican forms of government" (Bonner p. 52)—quotations taken from later Confederate sources. The secessionists thought very highly of the old constitution of the "former USA", which they adopted as their own. Some even advocated to simply adopt the USA flag, because the Confederacy stood for the values it represented, while the North had abandoned them. Most wanted at all price to preserve at least its colours. And thus it happened. The designer of the later confederate battle flag wrote: The three colors of which it is composed, red, white and blue, are the true republican colors. (Preble p. 506)
The colours were symbolically re-interpreted by the founding fathers of both the USA and the CSA, but, originally, "blue" is the sky above Scotland, "red" is the blood-and-fire of the warrior archangel Michael, and "white" is both clouds in the Scottish sky and St. Michael's purity.