Exactly 150 years ago this Tuesday, Confederate Captain Henry Wirz climbed the steps of the gallows in the courtyard of the Old Capitol Prison in Washington, D.C., where the U.S. Supreme Court building now stands. A hood and noose were placed over his head, and the trapdoor flew open. The fall did not snap his neck but left him to slowly strangle. The crowd of some 250 witnesses cheered and applauded. The life of America’s most notorious war criminal was over, but the battle over his legacy was just beginning.

Confederate Captain Henry Wirz

Wirz, the commandant of the Confederacy’s prisoner of war camp in Andersonville, Georgia, was perhaps the second-most hated person in America, after John Wilkes Booth. “There are deeds, crimes that may be forgiven; but this is not among them,” Walt Whitman wrote of Wirz’s crimes. “It steeps its perpetrators in blackest, escapeless, endless damnation.” And yet, not far from the graves of Wirz’s victims stands a monument celebrating the man responsible for their horrific deaths.

During Wirz’s fourteen months in charge of Andersonville, 13,000 Union prisoners of war died from disease, starvation, exposure, medical neglect and murder. At its peak in August of 1864, more than 33,000 POWs were held in 26 acres of open ground. The only source of water was a small creek which ran dark with sewage. Rations, if they came at all, were barely enough to sustain life. Prisoners were never issued clothing or provided shelter, and lay under makeshift tents or in holes dug in the ground wearing the same ragged pieces of their uniforms for the duration. Everything in the camp, a prisoner later testified, was covered in lice and overrun with vermin. Witnesses also testified that Wirz personally murdered and tortured prisoners, and ordered guards to do the same.

Returned federal prisoners from Andersonville. Library of Congress

No Civil War prisoner of war camps, North or South, were country clubs. At the converted state prison in Alton, Illinois, more than 1,500 Rebels died in custody from disease. But no prison approached the death rate or deliberate cruelty of Andersonville. After the surrender at Appomattox, stories of survivors began flooding the Northern newspapers. The photographs of the survivors, starved into living skeletons, were like nothing the world had seen before and would not see again until the liberation of Nazi death camps at the end of World War II. Wirz was arrested and taken to Washington.

The Andersonville prisoner of war camp. Library of Congress

Wirz, a native of Zurich, Switzerland, presented a defense in his heavy German accent that he was only following orders. He claimed he could not feed the prisoners adequately because the South had no food to spare. Wirz blamed the overcrowding on the North’s refusal to continue the practice of exchanging prisoners. (He did, in fact, parole five prisoners to go to Washington to ask the Union to take some of the prisoners off his hands. After the Union refused them, the five men, as they had promised, returned to Andersonville.)