But history shows that Miles' design was rejected by Confederate leaders, never offically becoming the official flag of the Confederacy. Instead, it was adopted by Confederate General Robert E. Lee as the battle flag for the Army of Northern Virginia. Lee's army used it in battle beginning in December 1861 until the fall of the Confederacy.
https://www.loudountimes.com/news/controversial-confederate-flag-was-born-in-northern-virginia/article_8b1c4bc7-086f-529c-8c17-f51dd0813952.html