About Katherine Mackay (Duer)
Katherine Duer Mackay (1880–1930) was a beautiful debutante from an old, high society, New York family. She met wealthy American financier Clarence Mackay on a steamship crossing between New York and England in about 1897. They fell in love and were married on May 17, 1898. Harbor Hill, the site of their future estate with the striking view of Hempstead Harbor, was Katherine's and Clarie's wedding present from the senior Mackays. Katherine oversaw much of the design and building of their mansion at Harbor Hill. Katherine was a suffragette and a champion of women's rights and became the first woman member of the Roslyn school board in 1905.
Katherine left Clarence and her three children to run away with Clarence's doctor, Dr. Joseph Blake in 1910. The marriage officially ended in divorce in Paris in 1914. Katherine returned to New York in 1930, the same year she died from cancer.