Born Catherine Lucy Wilhelmina Stanhope, married first Archibald, Lord Dalmeny (1809-1851) and later Harry George Vane, 4th duke of Cleveland. "The 5th earl's mother was Catherine Lucy Wilhelmina, only daughter of Philip Henry, 4th Earl Stanhope; she was thus a sister of Earl Stanhope, the historian, and a niece of Lady Hester Stanhope, who was the niece of William Pitt. A celebrated beauty, a maid of honour and bridesmaid of Queen Victoria, she married, on the 20th of December 1843, Archibald, Lord Dalmeny (1809-1851), member for the Stirling Burghs, who became a lord of the admiralty under Melbourne. After his death she became the wife of Harry George Vane, 4th duke of Cleveland, and died in 1901." [http://en.wikisource.org/wiki/1911%20Encyclop%C3%A6dia%20Britannica/Rosebery,%20Archibald%20Philip%20Primrose,%205th%20Earl%20of] The Honourable Lady Catherine Primrose was the daughter of Philip Stanhope, 4th Earl Stanhope (7 December 1781 – 2 March 1855). She married Lord Dalmeny and was the mother of the future Prime Minister Archibald Philip Primrose, 5th Earl of Rosebery, 1st Earl of Midlothian, KG, PC (7 May 1847 – 21 May 1929). She remarried in 1854 to Harry George Powlett, 4th Duke of Cleveland (19 April 1803 – 21 August 1891), who was styled Lord Harry Vane. [http://en.wikipedia.org/wiki/Harry%20Powlett,%204th%20Duke%20of%20Cleveland]