Heinrich Himmler was head of all SS units, the Sicherheitspolizei, (Secret Police), the Ordungspolizei (public order police), and the concentration and extermination camps. He was one of Hitler's most important advisors, and after Hitler, the most feared man in the Third Reich. Himmler was responsible for enforcing Nazi ideology with respect to racial purification. At the end of 1941, the Endlösung (final solution) was adopted. Himmler assigned Reinhard Heydrich to execute this plan.