The Gross-Rosen concentration camp (Rogoźnica in Polish) was situated approximately 60 kilometres south- west of Wrocław. It was founded in the summer of 1940, originally as a satellite camp of Sachsenhausen, in the vicinity of a granite quarry. Just under a year later, on the 1st of May 1941, Gross-Rosen became an independent concentration camp, operating until February 1945. Its commanders, in turn, were Arthur Rödl, Wilhelm Gideon and Johannes Hassebroek. At the start, the camp's prisoners were made to work in the quarry, owned by the SS-Deutsche Erd und Steinwerke GmbH, and on the construction of the camp itself. Further auxiliary camps were gradually established in the area. The number of prisoners in the camp rose steadily, from approximately one and a half thousand in 1941 to almost a hundred thousand when the camp was closed. The total number of people imprisoned in Gross-Rosen during the war is close to 125 000 victims of various nationalities. Jews formed the largest group. It is estimated that about a third of all the camp's prisoners died there. The Jewish prisoners suffered under particularly cruel and inhuman working conditions, under the supervision of sadistic Nazi guards. Heavy labour for very small food rations led to a high death rate. Jewish prisoners were not allowed to receive medical care, and they were banned from talking to other prisoners.