Established in 1905, with offices at 251 South Fourth, Zantzinger & Borie flourished until Milton B. Medary
entered the firm in 1910, revising the title to Zantzinger, Borie & Medary
. After Medary's death in 1929, the name of the office reverted to Zantzinger & Borie.
Early work from the office reflects the common experience of many early twentieth century firms: a number of residences, the West Philadelphia branch of the Free Library, and several entries into competitions, most of them unsuccessful. Style choices also reflected the eclecticism produced by many offices of the time; however, this changed when Medary entered the firm. With his strong predeliction for the medieval, Medary led the partners into the collegiate gothic which would become the hallmark of their own style. After his death the office continued with many of the clients established during the Medary years, but a new sense of modernism was also injected during the 1930s, evident in the undated photograph of a rendering for the Burholme branch of the Corn Exchange National Bank.