When the German Wehrmacht invaded Poland in 1939, Marianne Rosner was living in Warsaw with her husband Herman and their son Aleksander. Herman Rosner was a well-known musician. In 1941 the family had to move into the Kraków ghetto. Marianne Rosner had to perform forced labor outside the ghetto, often having to leave Aleksander alone.
After the Kraków ghetto was liquidated in March 1943, Marianne Rosner was taken to Plaszow forced labor camp. She was responsible for around 300 prisoners there, as a barrack elder. She went hungry and was maltreated by the guards. Her husband and son were also imprisoned in the camp, but she was rarely able to see them. In 1944 Marianne Rosner was placed in the list of forced laborers to be transferred to Oskar Schindler’s ammunition factory in Brünnlitz. Instead, however, she was deported to Auschwitz-Birkenau along with other women prisoners. After around three weeks, Oskar Schindler managed to get the women back from Auschwitz. Marianne Rosner was liberated in Brünnlitz. After the war, she and her husband and son emigrated to the United States, where she changed her first name to Manci.