Hitler signed a "euthanasia decree"

In October 1939 Hitler signed a "euthanasia decree" backdated to 1 September 1939 that authorized Reichsleiter Philipp Bouhler, the chief of Hitler's Chancellery, and Karl Brandt, Hitler's personal physician, to carry out a program of involuntary euthanasia. After the war this program came to be known as Aktion T4, named after Tiergartenstraße 4, the address of a villa in the Berlin borough of Tiergarten, where the various organizations involved were headquartered.