father-figure, Walter Gropius, in 1941 over a very minor issue but the major reason may have been to get himself out from under the better-known name that dominated their practice. Breuer had married their secretary, Constance Crocker Leighton, and after a few more years in Cambridge, moved down to New York City in 1946 (with Harry Seidler as his chief draftsman) to establish a practice that was centered there for the rest of his life. He became a naturalized American citizen in 1944. New York City The Geller House I of 1945 (demolished in 2022) was one of the first to employ Breuer's concept of the 'binuclear' house, with separate wings for the bedrooms and for the living / dining / kitchen area, separated by an entry hall, and with the distinctive 'butterfly' roof (two opposing roof surfaces sloping towards the middle, centrally drained) that became part of the popular modernist style vocabulary. Breuer built two houses for himself in New Canaan, Connecticut: one from 1947 to 1948, and the other from 1951 to 1952. A demonstration house set up in the MoMA garden in 1949 caused a flurry of interest in the architect's work, and an appreciation written by Peter Blake. When the show was over, the "House in the Garden" was dismantled and barged up the Hudson River for reassembly on the Rockefeller property, Kykuit, in Pocantico Hills, New York. In 1948, Ariston Club, Breuer's only work in Latin America, was built in Mar del Plata, Argentina. His first two important institutional buildings were the UNESCO Headquarters in Paris finished in 1955 and the monastic Master Plan and Church at Saint John's Abbey in Minnesota in 1954 (again, in part, on the recommendation of Gropius, a "competitor" for the job, who told the monks they needed a younger man who could finish the job.) These commissions were a turning point in Breuer's career: a move to larger projects after years of residential commissions and the beginning of Breuer's adoption of concrete as his primary medium. Breuer was a supporter of the Council for the Advancement of the Negro in Architecture (CANA) and employed Beverly Lorraine Greene, the first African-American woman to be licensed as an architect in the United States. She is credited as draftsperson on a number of projects Breuer worked on in the 1950s including the Grosse Pointe Public Library. In 1966 Breuer completed the Whitney