There was a common saying in Germany in the 1930s, “Lieber Gott, mach mich dumm, damit ich nicht nach Dachau kumm” (Dear God, make me dumb, that I might not to Dachau come.” KZ Dachau and its descendant camps were the Nazis’ principal instrument of intimidation for anyone regarded as a threat to the Nazi goal of a German people’s community.

Dachau, the first official concentration camp in Germany, opened in March of 1933. Prior to its opening, prisoners of the regime were held in ordinary prisons like Stadelheim and Landsberg, as well as “informal prisons”, usually abandoned buildings commandeered by the Stormtroopers, who’d drag their victims there for impromptu torture sessions.

Legally, many prisoners taken into the concentration camp system were incarcerated under “protective custody” orders. Protective custody in this case meant protecting the people’s community from the prisoner. At this time, being Jewish was neither a necessary nor a sufficient condition for being placed in protective custody. To qualify, a prisoner had to belong to one of several proscribed groups: communists, social democrats, clergy, trade unionists, and members of other opposition political parties.

Those prisoners not in a concentration camp under protective custody orders were held instead under “preventative arrest” orders. Soon after the Nazis took power, they passed laws enabling police and the Gestapo to arrest those they consider likely to commit crimes in the future, even if the person had done nothing yet.

During 1933, the camp system expanded many times over, as every regional district (Gau) opened its own facility to terrify the opposition. Though propaganda films of the era portrayed these prisons as places where well treated inmates were sent to think on their sins against the people’s community, they were instead instruments of forced labor, torture, starvation, and (frequently) death.

However, it should be noted that the purpose of the concentration camps of the 1930s, unlike that of the extermination camps with which they’re often conflated, was not necessarily to kill the prisoners. Prisoner deaths were common, primarily because the rules of the camps made it easy for guards to kill their charges and chalk their deaths up to accident, escape attempts, attacks by prisoners on guards or other inmates, or other prisoner infractions. Still, the primary objective was intimidation, not just of the inmate, but of the population at large. The average Dachau prisoner spent eighteen months in the camp, after which he was usually sent home, often a broken man. The sight of such a person in the neighborhood pub or on the street was generally a more useful reminder of what it meant to oppose the Nazi regime than a corpse would have been.

In 1934, Heinrich Himmer, the head of the SS, centralized the administration of concentration camps, placing Theodor Eicke, the commandant of Dachau concentration camp, in charge of the Inspectorate of Concentration Camps. Eicke set about reducing the number of camps, moving prisoners into fewer, larger facilities. He also set the guidelines for how camps were to be run and how guards were to be trained.

Jewish populations in the camp started to expand after the Nuremberg laws were passed in 1935. Once Jews who’d been convicted of crimes under the Nuremberg laws were released from ordinary prison, they were taken into protective custody by the SS. As with other prisoners, there were no options for extricating Jews from these places. The entire concentration camp system had been placed, by Hiter’s fiat, beyond the reach of the courts and the law. Jewish populations in these camps would expand even more after Kristallnacht, in November 1938.

As the Reich started to expand, beginning with the annexation of Austria, the camp system expanded with it. KZ Mauthausen, for example, was built to punish what the Nazis considered the worst of the worst. They were worked, often to death, in quarries that were to deliver the marble needed for the Albert Speer’s massive German stadium at Nuremberg’s Nazi party rally grounds and for the brodbignadian buildings of the new Berlin, or Germania, as Hitler called it.

By the time war broke out, the German concentration camp system had trained a large contingent of men and women to be what Hitler wanted his operatives to be in the East: cold, violent, and sadistic without limit. These were the people Hitler would now trust to annihilate entire populations whose mere existence supposedly threatened the Nazi dream.