The Schutzstaffel (, translated to Protection Squadron or defence corps, abbreviated SS—or with stylized "Armanen" sig runes) was a major paramilitary organization under Adolf Hitler and the Nazi Party (NSDAP). It began at the end of 1920 as a small permanent guard unit known as the "Saal-Schutz" (Hall-Protection) made up of NSDAP volunteers to provide security for Nazi Party meetings in Munich. Later in 1925, Heinrich Himmler joined the unit which had by then been reformed and renamed the "Schutz-Staffel". Under Himmler's leadership (1929-1945), it grew from a small paramilitary formation to one of the largest and most powerful organizations in the Third Reich. Built upon the Nazi ideology, the SS under Himmler's command was responsible for many of the crimes against humanity during World War II (1939–1945). The SS, along with the Nazi Party, was banned in Germany as a criminal organization after 1945.