The Reich Main Security Office (RSHA) was a secret police, security, and intelligence agency of Nazi Germany that existed from 27 September 1939 to 8 May 1945, uniting the Sicherheitsdienst (SD) and Sicherheitspolizei (SiPo). Headed by Heinrich Himmler, the RSHA's goal was to fight all enemies of the Reich both inside and outside of Germany, and it was divided into seven departments: the Administration and Legal Department, the Ideological Investigation Department, the Spheres of German Life Department, the Suppression of Opposition Department (Gestapo), the Suppression of Crime Department (Kripo), the Foreign Intelligence Service, and the Ideological Research and Evaluation Department. From 1939 to 1942, Reinhard Heydrich was its executive; Himmler was acting director from 1942 to 1943 following Heydrich's assassination, and Ernst Kaltenbrunner headed it from 1943 to 1945.