In summer 1942, several members of the White Rose had to serve for three months on the Russian front alongside many other male medical students from the University of Munich. There, they observed the horrors of war, saw beatings and other mistreatment of Jews by the Germans, and heard about the persecution of the Jews from reliable sources. Some witnessed atrocities of the war on the battlefield and against civilian populations in the East. In a letter to his sister Anneliese, Willi Graf wrote: "I wish I had been spared the view of all this which I had to witness." Gradually, detachment gave way to the conviction that something had to be done. It was not enough to keep to oneself one's beliefs, and ethical standards, but the time had come to act.