On September 22, 1939, the SD (Security Service) and Sipo (the Security Police) merged and became the Reich Security Main Office (RSHA). Under the command of Heydrich, the RSHA evolved between 1939 and 1941 into a mammoth organisation that eventually included seven departments: Personnel; Organisation and Law; Internal Affairs; Gestapo; Criminal Police (Kripo); Intelligence; and, Ideological Affairs.