History
Until early 1940, the largest group of inmates consisted of German, Austrian and Czechoslovak socialists, communists, anarchists, homosexuals, and people of Roma origin. Other groups of people to be persecuted solely on religious grounds were the Sectarians, as they were dubbed by the Nazi regime, meaning Bible Students and Jehovah's Witnesses. The reason for their imprisonment was their total rejection of giving the loyalty oath to Hitler and their absolute refusal to participate in any kind of military service.
In early 1940, a large number of Poles were transferred to the Mauthausen-Gusen complex. The first groups were mostly composed of artists, scientists, Boy Scouts, teachers, and university professors, who were arrested during the course of the AB Action.
Throughout the years of World War II, the camps of Mauthausen-Gusen received new prisoners in smaller transports on a daily basis; mostly from other concentration camps in German-occupied Europe. Most of the prisoners in the sub-camps of Mauthausen were kept in various detention sites prior to transportation to their final destination. The most notable of such centres for Mauthausen-Gusen were the infamous camps at Dachau and Auschwitz. The first transports from Auschwitz arrived in February 1942. The second transport in June of that year was much larger and numbered some 1,200 prisoners. Similar groups were sent from Auschwitz to Gusen and Mauthausen in April and November 1943, and then in January and February 1944. Finally, after Adolf Eichmann visited Mauthausen in May of that year, KZ Mauthausen-Gusen received the first group of roughly 8,000 Hungarian Jews from Auschwitz; the first group to be evacuated from that camp before the Soviet advance. Initially, the groups evacuated from Auschwitz consisted of qualified workers for the ever-growing industry of the Mauthausen-Gusen camp complex, but as the evacuation proceeded other categories of people were also transported to Mauthausen, Gusen, Vienna or Melk.
As in all other German concentration camps, not all the prisoners were equal. Their treatment depended largely on the category assigned to each inmate, as well as their nationality and rank within the system. The so-called kapos, or prisoners who had been recruited by their captors to police their fellow prisoners, were given more food and higher pay in the form of concentration camp coupons which could be exchanged for cigarettes in the canteen, as well as a separate room inside most barracks. In addition, following Himmler's order in June, 1941, a brothel was opened for them in 1942, in the Mauthausen and Gusen I camps. The Kapos formed the main part of the so-called Prominents (German: Prominenz), or prisoners who were given a much better treatment than the average inmate.
*source: wikipedia.org