 Complete the following phrase:  During the Civil War, Walthall entered the Confederate Army as a lieutet in the 15th Mississippi Infantry on April 27, 1861, and was promoted to lieutet colonel on July 21, 1861. He fought with his regiment at the Battle of Mill Springs on January 19, 1862. Walthall was elected colonel of the 29th Mississippi Infantry on April 11, 1862 and fought at the Siege of Corinth and in the 