Irena was born in Poland in 1910. Her father was a doctor, Stanisław Krzyżanowski, and many of his patients were poor Jewish families.
When Irena was seven, he caught typhus from those patients, and he died.
He left her one lesson. "If a man is drowning, it is irrelevant what is his religion or nationality," he told her. "One must help him."
By 1939, Irena was a social worker for the city of Warsaw. That year, the Germans invaded Poland.