She devoted her adult life to defending her father's public image from attack and continuing his tradition of philanthropy. In 1920, she went back to Europe, revisiting sites she had known before the war, taking pictures and documenting the damage. In northern France, traveling through
Berry-au-Bac and on to
Soissons, she was appalled at the destruction, particularly to
Soissons Cathedral. She photographed the damage, accumulating a record of the devastation wrought during the war. It was on that trip that she came to blame the Germans for damaging sites she had visited before the war, an attitude that would strengthen throughout her life. Eventually the references were moved to New York where the
Frick Art Reference Library opened in 1924, In the mid-1920s she responded to
John Gabbert Bowman's request for funding the
University of Pittsburgh. The institution was deeply in debt and had cut fine arts courses, but the acquisition of land in Oakland that previously belonged to the Frick estate provided space in
Oakland for expansion. Bowman wanted to build a "cathedral of light" there; Helen funded the university's fine arts department with the proviso of "having the final selection of the department head." She went on to endow and found the university's teaching collection in 1928, Early in the 1930s, after the 1931 death of her mother, she hired
John Russell Pope to expand the Frick Reference Library into two adjacent townhouses. Pope built abundant shelving and windows, and a medieval-style office for Helen.
Time magazine said of the building, it was "instantly recognized as one of the most important art libraries in the world." Between 1922 and 1967, Helen commissioned 57,000 large format negatives. In Italy church interiors were lit, making it possible to photograph centuries-old frescoes and altarpieces, such as the now-lost frescoes by
Giovanni Baronzio. More than 8,000 photographs are attributed to Italian photographer Mario Sansoni, who worked for Helen for many years. Worried at the outbreak of World War II and reminded of the devastation she witnessed during World War I, in 1941 Helen had every single record in the art archives microfilmed, which were stored, at first, in an underground
bank vault, and later moved to the Midwest. As early as 1943, the Committee for the Protection of Cultural Treasures in War Areas was consulting with the library, compiling lists for the
Monuments, Fine Arts, and Archives program, which located, identified and returned looted art at the end of World War II. , now the site of the Frick Collection The family's home on 5th Avenue was transformed into the Frick Collection in 1935. Helen continued as a trustee, to be active in acquisitions. A small woman, described as a "frail little woman," Helen was often in conflict with the male board members, in particular with
John D. Rockefeller, whom her father had also appointed as trustee to the Frick Collection. The two fought over the manner in which the house should be transformed into a museum, whether the costly furniture should be kept (she wanted it, he did not), and Helen resisted his efforts to add pieces from his own collection. She eventually resigned the position in 1961, "in a fury," after gifts were accepted from Rockefeller. ==Later years==