that their marriage would break the laws of the Roman Catholic Church by allowing Kathleen's children to be raised in the Church of England (Anglican Communion) rather than the Roman Catholic Church. Rose even tried to manipulate their relationship by keeping Kathleen away from Hartington and postponing a possible wedding. Regardless, Kathleen married Hartington on May 6, 1944, in a civil ceremony at the Caxton Hall Register Office. Kathleen's eldest brother Joseph P. Kennedy Jr., an officer in the United States Navy, to whom she had grown close during the last year of his life, as he was serving in Britain, was the only member of the family to attend the ceremony. Her second eldest brother, John, was still hospitalized due to a back injury incurred on the motor torpedo patrol boat PT-109 in the South Pacific Ocean, while her younger brother, Robert F. Kennedy, was in naval training. On August 12, 1944, Joe Jr. was killed when his plane exploded over the English Channel during a top-secret bombing mission in Europe. Widowhood Kathleen, now Marchioness of Hartington, and Lord Hartington spent less than five weeks together before he went out to fight in France. Four months after their marriage, and less than a month after Joe Jr. was killed, Hartington was killed by a sniper during a battle with the Germans in Belgium. With his family's blessing, he was buried close to where he fell. His younger brother Lord Andrew Cavendish, who was married to Deborah Mitford, one of the Mitford sisters, thus became the heir apparent to the dukedom, as Billy Hartington had left no heir. Popular on the London social circuit and admired by many for her high spirits and wit, Lady Hartington eventually became romantically involved with the 8th Earl Fitzwilliam, who was in the process of divorcing his wife. Once again, Rose Kennedy expressed her disapproval of her daughter's suitor and warned Kathleen that she would be disowned and cut off financially if she married Lord Fitzwilliam. In May 1948, Kathleen learned that her father would be traveling to Paris. In an effort to gain his consent for her upcoming plans to marry Fitzwilliam, she decided to fly to Paris to meet with her father. Death On May 13, 1948, Lady Hartington and Lord Fitzwilliam were flying from Paris to the French Riviera for a vacation aboard a de Havilland DH.104 Dove. At 3:30 in