Henry Wirz was born Hartmann Heinrich Wirz in Zurich in 1823, the son of a master tailor, and was convicted of fraud and embezzlement in 1847, a sentence commuted to 12 years of exile while his wife divorced him. This episode follows him to the United States in 1849, from a Massachusetts factory to work as a doctor’s assistant in Kentucky, a homeopathic practice, a water cure clinic and a post as overseer on a Louisiana plantation. He enlisted as a Confederate private in 1861, later claimed a Seven Pines wound that historians doubt, and became adjutant to General John H. Winder before taking charge of the interior of Camp Sumter, known as Andersonville, in April 1864.

Andersonville was an open stockade of 16.5 and later 26 acres with no barracks, holding about 33,000 prisoners at its peak; of 45,000 men who passed through, nearly 13,000 died. Wirz requested supplies and let five prisoners carry a petition for exchange north, but he also enforced the deadline. Tried by a military commission under Lew Wallace from August to October 1865 while lying on a sofa with gangrene, he was convicted and hanged on November 10, 1865, after refusing a deal to implicate Jefferson Davis. His trial’s rejection of the following orders defense later echoed at Nuremberg.

• Of 158 prosecution witnesses, 145 testified they never saw Wirz kill anyone.
• Witness Felix de la Baume claimed to be a French nobleman descended from Lafayette but was Felix Oeser, a deserter from the 7th New York.
• Defense witness James Duncan, a former camp guard, was arrested on arrival and accused of causing a death himself.
• The drop at his execution failed to break his neck, and two of his vertebrae were kept by a medical museum.
• An obelisk to Wirz stands in Andersonville, Georgia, and the Sons of Confederate Veterans gave him their Confederate Medal of Honor in the 1970s.