Up to this time no hint had been given me of what was wanted after I left Vicksburg, except the suggestion in one of Halleck's dispatches that I had better go to Nashville and superintend the operation of troops sent to relieve Rosecrans. Soon after we started the Secretary handed me two orders, saying that I might take my choice of them. The two were identical in all but one particular. Both created the "Military Division of Mississippi," (giving me the command) composed of the Departments of the Ohio, the Cumberland, and the Tennessee, and all the territory from the Alleghanies to the Mississippi River north of Banks's command in the south-west. One order left the department commanders as they were, while the other relieved Rosecrans and assigned Thomas to his place. I accepted the latter. We reached Louisville after night and, if I remember rightly, in a cold, drizzling rain. The Secretary of War told me afterwards that he caught a cold on that occasion from which he never expected to recover. He never did.