The Nazis established concentration camps immediately after they assumed power. The camps were built as large detention centers and prisons for political opponents and enemies of the state. These enemies and opponents included Communists, Social Democrats, Jehovah’s witnesses, dissident clergy, purged Nazis, “asocial types” (repeat offenders and homosexuals), gypsies, and arrested Jews.
The first concentration camp was built in Dachau, near Munich, in 1933. By 1939, Germany had six camps with approximately 21,000 prisoners. The camps were under the ultimate jurisdiction of SS Reichsfuehrer Henrich Himmler. Their day-to-day administration was the responsibility of Theodor Eicke, first commandant of Dauchau. After 1940, administrative responsibility passed to Oswald Pohl, a professional bureaucrat who established a chain of concentration and labor camps in Poland.
After the war broke out, the concentration camps overflowed with inmates. To support the expanding military effort, the Nazis drew upon the camps for a slave labor force that included Soviet prisoners of war, Poles, and resistance fighters from conquered nations. They controlled the inmates through random terror and arbitrary executions. One detail is sufficient to suggest how vast the system was: concentration camps employed over 40,000 people as guards.