Harry Waldron Havemeyer was the son of Horace Havemeyer [1886-1956] and his wife, née Doris Anna Dick [1890-1982], and the grandson of sugar refiner Henry Osborne Havemeyer [1847-1907] and his wife, née Louisine Waldron Elder [1855-1929]. Louisine Waldron Elder was born in New York City, the daughter of George W. Elder [1831-1873], also a sugar refiner, and his wife, née Mathilda Adelaide Waldron [1834-1907]. In 1873, while attending the fashionable Paris boarding school of Mme. Marie Del Sarte, Louisine met the American painter Mary Cassatt, who helped to introduce her to the avant-garde schools of Impressionism and Post-Impressionism. Soon afterward, Louisine became the first American patron of Degas. Louisine married Henry Osborne Havemeyer [1847-1907] on 22 August 1883. Henry was divorced from Louisine's aunt, Mary Louise Elder [1847-1897]. Henry and Louisine had three children: Horace, Adaline [later Mrs. Peter H. B. Frelinghuysen, 1884-1963], and Electra [later Mrs. James Watson Webb, 1888-1960]. In 1899 the Havemeyers built a mansion on Fifth Avenue, with an interior designed by Louis C. Tiffany studios, where Mrs. Havemeyer entertained a diversified group of celebrities. The Havemeyers soon became dedicated and discerning art collectors. Mrs. Havemeyer herself made more than 30 transatlantic buying trips. At her death, Louisine bequested the collection to the Metropolitan Museum of Art. Horace Havemeyer, Sr., continued in the family sugar business, as President of Havemeyer's & Elder, ad well as holding offices in other refining, manufacturing, and banking enterprises. He and Doris had four children: Doris [1912-1975], Adaline [b. 1913], Horace Jr. [b. 1914], and Harry Waldron.
Weitzenhoffer, Frances. The Havemeyers: Impressionism Comes to America. New York, 1986.