After the war, Wirz was tried and executed for conspiracy and murder relating to his command of the camp; this made the captain the highest-ranking soldier and only officer of the Confederate Army to be sentenced to death for crimes during their service.

[2] Since his execution, Wirz has become a controversial figure due to debate about his guilt and reputation, including criticism over his personal responsibility for Andersonville Prison's conditions and the quality of his post-war trial.

[6] He tried to establish his own homeopathic medicine practice in Cadiz, Kentucky, and also worked as superintendent of a water cure clinic in Northampton, Massachusetts.

[6] In 1856 Wirz made the acquaintance of Levin R. Marshall, the owner of the plantation Cabin Teele, who employed him as its overseer and where he set up a practice for homeopathic medicine.

[10][11] 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,[12] one of whom says the injury may have actually occurred during a six-thousand mile mission to track down missing records of Union prisoners.

"[citation needed] 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.

[1] Wirz returned from Europe in January 1864 and reported to Richmond, Virginia, where he began working for General Winder in the prison department.

[citation needed] 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.

Camp Sumter suffered from severe overcrowding, poor sanitary conditions, and an extreme lack of food, tools, medical supplies, and potable water.

Wirz was charged with "combining, confederating, and conspiring, together with John H. Winder, Richard B. Winder, Joseph [Isaiah H.] White, W. S. Winder, R. R. Stevenson, and others unknown, to injure the health and destroy the lives of soldiers in the military service of the United States, then held and being prisoners of war within the lines of the so-called Confederate States, and in the military prisons thereof, to the end that the armies of the United States might be weakened and impaired, in violation of the laws and customs of war" and for "violation of the laws of war, to impair and injure the health and to destroy the lives—by subjecting to torture and great suffering; by confining in unhealthy and unwholesome quarters; by exposing to the inclemency of winter and to the dews and burning sun of summer; by compelling the use of impure water; and by furnishing insufficient and unwholesome food—of large numbers of Federal prisoners.

[24] The National Park Service lists 158 witnesses who testified at the trial, including former Camp Sumter prisoners, ex-Confederate soldiers, and residents of nearby Andersonville.

[28] In early November 1865, the Military Commission found Wirz guilty of conspiracy as charged, along with 10 of 13 specifications of acts of personal cruelty, and sentenced him to death.

[29] In his report on the trial, the Judge Advocate General Joseph Holt, who had prosecuted the Lincoln assassination trials, vilified Wirz and pronounced that "his work of death seems to have been a saturnalia of enjoyment for the prisoner [Wirz], who amid these savage orgies evidenced such exultation and mingled with them such nameless blasphemy and ribald jest, as at times to exhibit him rather as a demon than a man.

P. E. Bole received the same visitor and later sent a letter to Jefferson Davis, who included it as well as Wirz's reply to Schade in his book, Andersonville and Other War-Prisons (1890).

[2][citation needed] His neck did not break from the fall, and the crowd of 200 spectators guarded by 120 soldiers watched as he writhed and slowly strangled.

[34] In 1869, Schade received permission from President Johnson to rebury Wirz's body, which had been buried at the Washington Arsenal alongside the Lincoln assassins.

[19][41] Despite the surrounding controversy, the Wirz trial was one of the nation's significant early war crimes tribunals, creating enduring moral and legal notions and established the precedent that certain wartime behavior is unacceptable, regardless if committed under the orders of superiors or on one's own.

[42][43] Wirz is an important character in MacKinlay Kantor's Pulitzer Prize-winning novel Andersonville (1955), introduced in the third chapter during his mission to France in October 1863.