Upon the rise of Adolf Hitler and the National Socialist German Workers Party (the Nazi Party) in Germany, gay men and, to a lesser extent, lesbians, were two of the numerous groups targeted by the Nazis and were ultimately among Holocaust victims. Beginning in 1933, gay organizations were banned, scholarly books about homosexuality, and sexuality in general, (such as those from the Institut für Sexualwissenschaft, run by Jewish gay rights campaigner Magnus Hirschfeld) were burned, and homosexuals within the Nazi Party itself were murdered. The Gestapo compiled lists of homosexuals, who were compelled to sexually conform to the "German norm."
Between 1933 and 1945, an estimated 100,000 men were arrested as homosexuals, of whom some 50,000 were officially sentenced. Most of these men served time in regular prisons, and an estimated 5,000 to 15,000 of those sentenced were incarcerated in Nazi concentration camps. It is unclear how many of the 5,000 to 15,000 eventually died in the camps, but leading scholar Rüdiger Lautmann believes that the death rate of homosexuals in concentration camps may have been as high as 60%. Homosexuals in the camps were treated in an unusually cruel manner by their captors.
After the war, the treatment of homosexuals in concentration camps went unacknowledged by most countries, and some men were even re-arrested and imprisoned based on evidence found during the Nazi years. It was not until the 1980s that governments began to acknowledge this episode, and not until 2002 that the German government apologized to the gay community. This period still provokes controversy, however. In 2005, the European Parliament adopted a resolution on the Holocaust which included the persecution of homosexuals.