Aktion T4 (German, pronounced [akˈtsi̯oːn teː fiːɐ]) was a campaign of mass murder by involuntary euthanasia which targeted people with disabilities and the mentally ill in Nazi Germany. The term was first used in post-war trials against doctors who had been involved in the killings. The name T4 is an abbreviation of Tiergartenstraße 4, a street address of the Chancellery department set up in early 1940, in the Berlin borough of Tiergarten, which recruited and paid personnel associated with Aktion T4. Certain German physicians were authorised to select patients "deemed incurably sick, after most critical medical examination" and then administer to them a "mercy death" (Gnadentod). In October 1939, Adolf Hitler signed a "euthanasia note", backdated to 1 September 1939, which authorised his physician Karl Brandt and Reichsleiter Philipp Bouhler to begin the killing.
The killings took place from September 1939 until the end of World War II in Europe in 1945. Between 275,000 and 300,000 people were killed in psychiatric hospitals in Germany, Austria, occupied Poland, and the Protectorate of Bohemia and Moravia (now the Czech Republic). The number of victims was originally recorded as 70,273 but this number has been increased by the discovery of victims listed in the archives of the former East Germany. About half of those killed were taken from church-run asylums. In June 1940, Paul Braune and Fritz von Bodelschwingh, who served as directors of sanatoriums, protested against the killings, being members of the Lutheran Confessing Church.
