Question: What year did Heinrich Himmler join the unit that used the concept of Wehrbauer to refer to soldiers designated as settlers for the lands conquered during the German invasions of the Soviet Union and Poland?

Related documents: [0]  [DOC] The Schutzstaffel (SS; also stylized as with Armanen runes; ] ; literally "Protection Squadron") was a major paramilitary organization under Adolf Hitler and the Nazi Party (NSDAP) in Nazi Germany, and later throughout German-occupied Europe during World War II. It began with a small guard unit known as the "Saal-Schutz" (Hall-Protection) made up of NSDAP volunteers to provide security for party meetings in Munich. In 1925, Heinrich Himmler joined the unit, which had by then been reformed and given its final name. Under his direction (1929–45), it grew from a small paramilitary formation to one of the most powerful organizations in Nazi Germany. From 1929 until the regime's collapse in 1945, the SS was the foremost agency of security, surveillance, and terror within Germany and German-occupied Europe. [END] 
[1]  [DOC] Wehrbauer (] , "soldier peasant") was a concept used by the "Schutzstaffel" (SS) of the Nazi Party to refer to soldiers designated as settlers for the lands conquered during the German invasions of the Soviet Union and Poland. [END]  
Answer: 1925
1925