I’m willing to bet the flag you’re used to seeing is not the “Stainless Banner.”

The first flag chosen by the Confederate Congress to be their national flag (known, unsurprisingly, as “the first national”), was this one. It was colloquially known as “the Stars and Bars,” a nickname I have (incorrectly) seen given to variations on the battle flag. The flag was adopted (with seven stars, for the first seven states to secede) in early 1861, going through a few changes in the number of stars before settling on 13 late in the year (one for each of the eleven states to secede plus Kentucky and Missouri, which never officially seceded or were under Confederate control but exiled politicians represented the states in the Confederate congress).

You’ll notice something about that flag. It bears a striking resemblance to the US flag. That caused confusion at the First Battle of Bull Run/Manassas (in addition to the confusion coming from two green, largely militia armies being hastily assembled and thrown into battle with nothing approaching a standard uniform on either side). In that era, regiments carried flags into battle to aid in identification of other units and for the generals to pinpoint their locations. As you can imagine, having a flag that is difficult to distinguish from the enemy can cause all sorts of problems - both friendly fire incidents, and not firing on enemy units thinking that they’re friendly.

That confusion led General P.G.T. Beauregard to push for the creation of a “battle flag,” which resulted in this flag being adopted in late 1861. I’m willing to bet this one is more familiar to you, although in rectangular form (I’ll get back to that). It is important to note that this flag was not a national flag - you wouldn’t have seen it flying over any government buildings (that would have been the various national flags). It would have been carried by Confederate regiments on the battlefield, often with variations (many regiments added their regimental number and state as well as a list of battles they’d fought in, and some had completely unique flags of their own). It was particularly associated with the Army of Northern Virginia, the largest Confederate field army under Robert E. Lee (the army which fought in most of the Civil War battles you’ve probably heard of).

As the war went on, the Confederate Congress eventually did change the national flag to this one. The “second national” incorporates the battle flag into the canton of a white field; this is the one that was nicknamed “the Stainless Banner.” It was adopted as a national flag in 1863. This flag also caused some confusion, bearing a similarity to a flag of truce.

The final modification was the “third national,” this flag. It added a red bar to avoid the confusion of the flag resembling a pure white flag. The “third national” was adopted in March of 1865, which means its actual use was very short lived, as the Confederacy ceased to exist as a functional political unit shortly thereafter.

So what if the rectangular version of the battle flag? It was used. The Confederate Navy used it as the naval jack from 1863, and it was popular as a regimental battle flag in the Army of Tennessee in the western theater. Why this one became the most well-known after the war, when it was not a national flag nor the more common variation of the battle flag, I don’t know, someone more familiar with postwar developments will have to fill that part out.

I hope this helps give some context to what the flags were and how they were used. If you have any questions let me know!

Thank you! That clears it up