"The Confederate General"
Volume 4
William C. Davis, editor

"Major General Kirby Smith was sent to Knoxville in March 1862, and Marshall submitted his resignation in June. But a major Confederate invasion of Kentucky was being planned and Marshall was persuaded that his participation might be of help. He applied for reinstatement as of June 23, and while it may never have been acted on by Congress, Marshall was treated as if he had never resigned.

[later].....Marshall delighted many Confederate officials by resigning on June 17, 1863."