Rudolf Franz Ferdinand Höss (also Höß, Hoeß or Hoess; 25 November 1901 – 16 April 1947) was a German SS officer during the Nazi era who, after the defeat of Nazi Germany, was convicted for war crimes. Höss was the longest-serving commandant of Auschwitz concentration and extermination camp (from 4 May 1940 to November 1943, and again from 8 May 1944 to 18 January 1945). He tested and implemented means to accelerate Hitler's order to systematically exterminate the Jewish population of Nazi-occupied Europe, known as the Final Solution. On the initiative of one of his subordinates, Karl Fritzsch, Höss introduced the pesticide Zyklon B to be used in gas chambers, where more than a million people were killed.