The de Caros, Menkhoffs, and Mulvehills were three families of European immigrants who settled in New York and Brooklyn in the late 19th century, and eventually became connected through marriage.

Frank A. de Caro immigrated to the United States from Italy in 1884. He worked as a tailor and owned store that manufactured flags, uniforms, and banners. His company De Caro & D'Angelo Co. operated out of a storefront at 169-171 Grand Street in Manhattan. Frank de Caro was heavily involved in the city's Italian-American community and founded New York's Italian Chamber of Commerce. Frank de Caro was also a large supporter of Columbus Day and participated in efforts to have it declared a national holiday. Between 1909 and 1910, de Caro, along with other leaders in the Italian-American community, visited the White House to speak with President William Howard Taft to have Columbus Day legally recognized as a holiday. Their efforts were successful, and Taft declared Columbus Day a national holiday in 1910.

Frank A. de Caro married Anna Menkhoff In 1891. Anna Menkhoff was a German immigrant who had moved to New York with her parents August and Maria Meyer Menkhoff in the 1880s. The Menkhoffs owned and operated a pastry shop in New York, and Anna worked for her parents in the store. When Frank de Caro first started courting Anna Menkhoff, her parents expressed their disapproval and attempted to dissuade their daughter from marrying him. The Menkhoffs went so far as to buy a new piano for Anna as a way to distract their daughter from Frank's advances. They were ultimately unsuccessful and Frank and Anna eloped in 1891. Frank and Anna de Caro later had the receipt for the piano framed along with a letter Frank wrote to her parents announcing their elopement. The receipt and letter are included in this collection. Frank and Anna de Caro had seven children, Elsa, Francis, Lillyan, Frank E., Gertrude, Arthur, and William de Caro, who died as an infant. The family lived in Brooklyn at 725 Greenwood Avenue.

Frank and Anna de Caro's son Frank E. de Caro was born in Brooklyn in 1908. During the 1930s Frank E. de Caro worked as a stock broker on Wall Street and as a male model. In 1938 he married his long-time girlfriend Beatrice Mulvehill. Frank and Beatrice met at Lake Waramaug in Connecticut where both of their families spent summer vacations. The couple began dating in 1929, and eventually married in 1938. Frank was drafted during World War II and died in France in 1944. They had one son, Frank de Caro, who was born in 1943.

The Mulvehills were Irish immigrants who moved to Brooklyn in the 1840s. Beatrice's father John Henry Mulvehill (1873-1943) was born in Brooklyn in 1873 and had a successful career in the insurance business. He married Myrtle Bell Brown (1880-1963) from Russell County, Kansas and the couple had five children, Edward Leslie, John Joseph, Vincent Lyman, Urban Sylvester, and Beatrice Agnes. Many of Mulvehill's sons also worked in insurance, while their sister Beatrice worked for many years at the Brooklyn Public Library.