Rose Leveson-Gower, Countess Granville

On 24 May 1916, Lady Rose Bowes-Lyon married The Hon. William Leveson-Gower, who succeeded to his childless brother's earldom on 21 July 1939.[1] As a result, she was styled as Countess Granville.[1]

The couple had two children, Lady Mary Cecilia (12 December 1917 – 13 February 2014) and Granville James Leveson-Gower, 5th Earl Granville (6 December 1918 – 31 October 1996).

• Lady Mary Cecilia Leveson-Gower (12 December 1917 – 13 February 2014), who married Sir Samuel Clayton (8 January 1918 – February 2004) on 7 July 1956 and had issue. Their daughter is polar adventurer Rosie Stancer.
• Granville James Leveson-Gower, 5th Earl Granville (6 December 1918 – 31 October 1996), who married Doon Aileen Plunket (1931–2003) on 9 October 1958 and had issue.

The Countess Granville stood godmother to her niece, Princess Margaret Rose of York, at the latter's christening on 3 October 1930. She was invested as a Dame Grand Cross of the Most Venerable Order of the Hospital of St John of Jerusalem (GCStJ).[1] She was also awarded the honorary degree of Doctor of Laws (LL.D.) by Queen's University Belfast.[1] In 1953, she was invested as a Dame Grand Cross of the Royal Victorian Order (GCVO).[1]

Lord Granville died on 25 June 1953, aged 72. Lady Granville outlived him by fourteen years when she died on 17 November 1967, aged 77. She was the last surviving sibling of Queen Elizabeth The Queen Mother.