Otto Kallir knew Käthe Kollwitz when he lived in Vienna, and during that period he sold one of her drawings to the Albertina Museum. However, it was his later business partner, Hildegard Bachert, who made Kollwitz a mainstay of the Galerie St. Etienne in New York. Unlike the Austrian artists whom Kallir represented, Kollwitz had a reputation in the U.S. prior to World War II, and refugee collectors brought more of her work with them. Kallir and Bachert worked with August Klipstein on the first catalogue raisonné of the artist’s prints (1955), helping to establish a basis for future scholarship. Bachert became an expert in her own right, forming close relationships with the Kollwitz museums in Cologne and Berlin. She assisted Alexandra von dem Knesebeck with her 2002 catalogue raisonné of Kollwitz’s prints and Annette Seeler with her 2016 catalogue of the sculptures.