Reichsführer-SS was a special SS rank that existed between the years of 1925 and 1945. Reichsführer-SS was a title from 1925 to 1933 and, after 1934, became the highest rank of the German Schutzstaffel (SS).
Reichsführer-SS was both a title and a rank. The title of Reichsführer was first created in 1926 by Joseph Berchtold. Berchtold's predecessor, Julius Schreck, never referred to himself as Reichsführer but the title was retroactively applied to him in later years. In 1929, Heinrich Himmler became Reichsführer-SS and referred to himself by his title instead of his regular SS rank. This set the precedent for the Commanding General of the SS to be called Reichsführer-SS.
In 1934, Himmler's title became an actual rank after the Night of the Long Knives.
From that point on, Reichsführer-SS became the highest rank of the SS and was considered the equivalent of a Generalfeldmarschall in the German Army.
There was never more than one Reichsführer-SS in the SS, with Himmler holding the rank as his personal title and rank from 1934 to 1945.
In all, five people held the title of Reichsführer-SS during the twenty years of its existence. Three persons held the position as a title while two held the actual SS rank.
· Julius Schreck (1925–1926)
· Joseph Berchtold (1926–1927)
· Erhard Heiden (1927–1929)
· Heinrich Himmler (1929–1945)
· Karl Hanke (1945), the last leader of the SS, was appointed to the position in April 1945 but never learned of his promotion and was killed by partisans before word of his appointment reached him.
Source:Wikipedia: Picture courtesy of: U.S. National Archives.