(Saturday, May 6, 1944) — Kathleen Kennedy, the 24-year-old fourth child of Joseph and Rose Kennedy and a younger sister of future U.S. President John F. Kennedy, today married William “Billy” Cavendish, the Marquess of Hartington, in a civil ceremony at the Caxton Hall Registry Office in Westminster, London, England.

Her eldest brother Joseph P. Kennedy, Jr., whom she had grown close to during the last year of his life, was the only member of the Kennedy family to attend the ceremony.