[Lady Iris's parents also married without the need of the Royal Marriages Act.]
Lady Iris was the only child of the Marquess and Marchioness of Carisbrooke The Marquess was born HH Prince Alexander of Battenberg, the eldest son of Princess Beatrice, youngest child of Queen Victoria, and Prince Henry of Battenberg. Prince Alexander's engagement to Lady Irene Denison was announced on May 31, 1917. Three weeks later, the "conditions brought about by the present war" led to the announcement that "those Princes" of the King's family "who are his subjects and bear German titles, should relinquish these titles and henceforth adopt British surnames.." The Duke of Teck, brother off Queen Mary, would be made a marquess. His younger brother, Prince Alexander, married to Princess Alice of Albany, was made an earl. Prince Louis of Battenberg and his nephew, Prince Alexander, were also created marquesses.
Alexander's new title was Marquess of Carisbrooke, Earl of Berkhampsted and Viscount Launceston. The new Marquess' marriage to Lady Irene Dension, daughter of the Earl and Countess of Londesborough took place on July 19, 1917 at the Chapel Royal, St. James's Palace.
Lady Carisbrooke gave birth to the couple's only child, Lady Iris Mountbatten, at Kensington Palace on January 13, 1920. There would no heir to Alexander's peerages. This may not be a surprise as Alexander's marriage was probably arranged due to his sexual proclivities. He had a long time male companion, Simon Fleet.
It can be safely said that Lord and Lady Carisbrooke were not hands on parents. The family lived in a grace-and-favour apartment at Kensington Palace, where the only time Lady Iris "communicated with her father, mother or her royal grandmother, Princess Beatrice, was when a governess took her to the drawing room to say goodnight."
She witnessed her grandmother destroy many of Queen Victoria's diaries. She was one of Princess Marina of Greece's bridesmaids when she married Prince George, Duke of Kent, in 1934. Two years later, she was a train bearer at George VI's Coronation.
There is not a lot known about how Lady Iris came to meet the half-American Hamilton O'Malley-Keyes. Ham, as he was known, dropped Keyes not long before his wedding. Iris was not his first fiancee. In May 1938, his engagement to Angela Tod was announced in The Times. The engagement came to an official end on December 15, 1938.
Hamilton O'Malley was Roman Catholic. This made things difficult for Lady Iris as she lost her dynastic rights when she married Hamilton.
According to all sources, including the report in the Court Circular, Lady Iris and Captain O'Malley were married on February 15, 1941 at St. Paul's Roman Catholic Church, Hayward's Heath, in Sussex. The marriage took place at 3 p.m.
This marriage appears in St. Paul's Matrimonial Register, but this wedding was not the legal ceremony. The wedding was registered by the church, but this is not the marriage that appears in the official records. On the same day, Lady Iris and Hamilton O'Malley were married in the Parish Church in Balcome, West Sussex. This wedding ceremony was according to the "rites and ceremonies of the Established Church by Special License."
Lady Iris's marriage collapsed rather quickly largely due to Hamilton's abuse. She is alleged to have had affairs with black musicians. Iris had no support from her family when she left Hamilton, and she was largely shunned by her family. She was not allowed to attend her grandmother's funeral in 1944.
Hamilton served in the second world war, was briefly held as a prisoner of war, and after his return home in 1946, he and Iris were divorced. His second marriage took place in January 1947.
Lady Iris and Hamilton had no children. He did have four sons one daughter by his second wife.