Not The Confederate Flag?
This is not the confederate national flag: When the United States split in twain during the Civil War, this was the first flag her rebel half used: The Bonnie Blue, which she copied from the Republic of West Florida. No, really. This country existed: a border disagreement between Spain and the US over the Louisiana Purchase gave some local rebels an opportunity to take over a fort in 1810, declare independence, as required with a flag, and run a government -- for 78 days until the United States put an end to that.
Anyway, fast forward to the Civil War, and when Mississippi seceded from the Union, she adopted the flag of the tiny country that had been within her borders. And it became the unofficial flag of the rebellion, but not for long. Blue wouldn't do. That's a Yankee color. The new confederate government asked for design submissions and got several, including one from a German/Prussian artist in Alabama who possibly took design cues from the Austrian Empire. And Betsy Ross.
(Side note: while we are talking about misnamed flags, Betsy Ross probably didn't design this flag -- there's no evidence to support that she did, only stories from long after she died -- Lady Godiva style. But we're getting off track here.) The confederate government selected this as her official flag and named it the "Stars and Bars" -- so calling this the stars and bars is wrong on two counts: that's not its name, this is a cross. These are bars.
New flag adopted, off to war, but on the battlefield, the flag's similarity with the Union's was confusing, what with all the terror and smoke. Nonetheless, the Confederacy stuck with her flag, but her Army wanted to avoid friendly fire and so took one of the rejected designs and squarified it into a battle flag. The navy too liked this design and eventually switched, though using a brighter, presumably non-Yankee blue.
The popularity of the official flag decreased in the Confederacy as time went on (even as they kept increasing the stars), while the popularity of the battle flag grew. So in 1863, the Confederate Government tried again and went with white, sticking the battle flag in the corner. This was better in the sense that the flag looked less like the Yankees', but worse in that the international symbol of surrender was now in the background. The army stuck with theirs.
Two years later, the confederate government again changed the flag, adding a red bar and a new, tough name. Also, the design slightly rectangularlified the battle flag. This could no longer be mistaken for surrender and was the last flag, as 36 days later the Confederacy surrendered. So this design was never technically the flag of the confederate government -- but... close enough.