Irmgard was one of three children born to a Jewish family in the famous university city of Goettingen. The city had a small Jewish population, and only one synagogue. Irmgard's father, with his two brothers, owned a linen factory that had been founded by Irmgard's grandfather. Irmgard attended public school in the city.
1933-39: With the onset of the Depression in the 1930s, the family's factory went into decline. When the Nazis came to power in 1933, they confiscated the Rosenbergs' factory. Later, the family was evicted from their home; they relocated to Hamburg. There, despite Nazi restrictions that Jews not work for German companies, Irmgard managed to obtain a job in a department store as a sales apprentice and helped support the family.
1940-43: In late 1941 the Rosenbergs were deported, along with 1,000 Hamburg Jews, 800 miles east to the Minsk ghetto in the Soviet Union. On arrival, they were herded by SS guards to a large red school. There were bodies strewn on the ground outside. Some of the new arrivals were ordered to drag away the corpses, clear half-eaten food from the tables and scrub the blood from the walls. Some prisoners told them that the Nazis had killed thousands of Soviet Jews to make room for the new transports.
Irmgard's brother Heinz was taken to the Treblinka extermination camp in the fall of 1943. The Minsk ghetto was liquidated soon after. Irmgard and her family were never heard from again.