This is part of the correspondence for the battle flags made in New Orleans by Henry Cassidy for Bragg's and Polk's Corps of the Army of the Mississippi. Bragg's flags arrived just in time for Shiloh with them being issued literally as the corps was marching out of Corinth. The Bragg Pattern flags (as we call them) did not arrive in time for Shiloh for Polk's Corps (and there's detailed correspondence for those as well) until after Shiloh.

The Mississippi High Pressure Brigade of James Chalmers bore these in battle at Shiloh and a couple survive today as I am sure you know. These were the somewhat square flags with 12 white stars with 6 points and yellow borders.

There's a lot of this correspondence at the National Archives in the correspondence books for that army.

Greg Biggs