Initially a small bodyguard unit under the auspices of the SA, the Schutzstaffel (SS; Protection Squadron) grew to become one of the largest and most powerful groups in Nazi Germany.[227] Led by Reichsführer-SS Heinrich Himmler from 1929, the SS had over a quarter million members by 1938.[228] Himmler initially envisioned the SS as being an elite group of guards, Hitler's last line of defence.[229] The Waffen-SS, the military branch of the SS, evolved into a second army.