I re-read "Shiloh In Hell Before Night" and on page 166 mentions that when Prentiss surrendered the Hornet's Nest position that a couple of Confederate Cavalrymen rode up and took the silk flag and banner of the 12th Iowa and dragged it through the mud. I went deeper and found this website that chronicles the flag bear. He carried the colors through every skirmish and battle the 12th were involved with from beginning to end, even after the regiment was exchanged after Shiloh and mustered back into service. And the amazing fact is, never was he so much as scratched in battle whilst members of the color guard were killed or wounded.