The battle flag of the Confederacy is square, of various sizes for the different branches of the service: 48 inches square for the infantry, 36 inches for the artillery, and 30 inches for the cavalry. It was used in battle from November 1861 to the fall of the Confederacy. The blue color on the Southern Cross in the battle flag was navy blue, as opposed to the much lighter blue of the Naval Jack. The Stars and Bars were too easily confused in the smoke of battle with the Stars and Stripes, resulting in very real military mistakes. To remedy this, General P.G.T. Beauregard of the Army of Virginia and others sought a better design and Beauregard was the first to adopt the flag from the design of William Porcher Miles (see below). Miles' rectangular design was sized down to a square to aid folding and carrying in battle.
This flag proved so popular, that it became basis for the Second National flag of the Confederacy (see above). Some prefer the square proportions of this flag over Mile's original rectangle as more sonorous and more distinct — and therefore a better symbol of the South.
The Confederate Navy Jack, also called "The Southern Cross," is rectangular, usually about 5×3 feet. The blue color in the saltire (the diagonal cross) is much lighter than in the Battle Flag, and it was flown only on Confederate ships from 1863 to 1865. This flag is what is typically recognized as the Confederate flag, but this is not strictly accurate.
The design was originally made by South Carolina Congressman William Porcher Miles to be the first national flag, but it was rejected by the Confederate government for looking too much like crossed suspenders. It was used by a few army units, including the Army of Tennessee as their battle flag. Today, it is the most universally recognized symbol of the South, where it is commonly called the rebel or Dixie flag.
Sometimes, the saltire is identified as "St. Andrew's Cross." But this is incorrect; Miles's proposals never mention this. "St. Andrew's cross" refers either to the national Flag of Scotland, a white saltire over a blue field, or the naval jack of Russia both before and after the Soviet Union, a blue saltire on a white field. St. Andrew is said to have been martyred on a diagonal cross and is a patron saint of Russia and the patron saint of Scotland. A legend dating from medieval times held that the cross washed up on Scottish shores. There is no connection with legends of St. Andrew and the South. While most white Southerners at the time of the War traced their ancestry to Britain, they tended to identify their heritage as Anglo-Saxon, though it is claimed around three-fourths of all people in the South were either Scots or Scotch-Irish during the 1800s.