William John Robert Cavendish, Marquess of Hartington
1917 - 1944 (26 years)(
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- 1 William John Robert Cavendish, Marquess of Hartington [1] b. 10 Dec 1917 d. 10 Sep 1944
- + Kathleen Agnes Kennedy b. 20 Feb 1920 d. 13 May 1948
- + Kathleen Agnes Kennedy b. 20 Feb 1920 d. 13 May 1948