Wirz enlisted as a private in Company A (Madison Infantry), 4th Battalion of Louisiana Infantry of the Confederate army in Madison Parish. Shortly before his death, he said that he had taken part in the Battle of Seven Pines in May 1862, as an aide-de-camp to General Joseph E. Johnston, during which he was wounded by a Minie ball and lost the use of his right arm. That account is disputed by historians, one of whom says the injury may have actually occurred during a six-thousand mile mission to track down missing records of Union prisoners. That journey and a subsequent three months of rehabilitation at his home, were completed by the end of 1862. After returning to his unit on June 12, 1862, Wirz was promoted to captain "for bravery on the field of battle." Because of his injury, Wirz was assigned to the staff of General John H. Winder, who was in charge of Confederate prisoner-of-war camps, as his adjutant. Later accounts by Wirz's daughter alleged that Confederate President Jefferson Davis made Captain Wirz a “special minister” and sent him to Europe carrying secret dispatches to Confederate Commissioners James Mason in England, and John Slidell in France. Wirz returned from Europe in January 1864 and reported to Richmond, Virginia, where he began working for General Winder in the prison department. Wirz initially served on detached duty as a prison commandant in Alabama, but was then transferred to help guard Union prisoners incarcerated at Richmond. Camp Sumter In February 1864, the Confederate government established Camp Sumter, a large military prison near the small railroad depot of Anderson (now Andersonville) in south-western Georgia, built to house Union prisoners-of-war. In April 1864, Wirz arrived at Camp Sumter and remained there for over a year holding the post of commandant of the stockade and its interior. Wirz was praised by his many superiors and even by some prisoners, and was even recommended for, but not promoted to, major. Camp Sumter had not been constructed to its full plan, and was quickly overwhelmed by the influx of Union prisoners. Though wooden barracks were originally planned, the Confederates incarcerated the prisoners in a vast, rectangular, open-air stockade originally encompassing , which had been intended as only a temporary prison pending exchanges of prisoners with the Union. The prisoners gave this place the name "Andersonville", which became the colloquial name for the camp. Camp Sumter