Lady Catherine Lucy Wilhelmina Stanhope was the third child and only daughter of Philip Henry Stanhope, 4th Earl Stanhope, FRS, and his wife Catherine Lucy Smith, daughter of Robert Smith, 1st Baron Carrington. She was known more familiarly as Wilhelmina in order to distinguish her from her mother. She was married at St. George's, Hanover Square, on September 20, 1843 to Archibald Primrose, Lord Dalmeny (1809-1851), eldest son of Archibald Primrose, 4th Earl of Rosebery, by whom she had issue four children, including Prime Minister Archibald Philip Primrose, 5th Earl of Rosebery. Following her first husband's death, she was married at Chevening on August 2, 1854 to Lord Harry Vane, who succeeded his brother in the dukedom of Cleveland in 1864, and changed his surname to Powlett. They had no children.
The Duchess of Cleveland was an English historian and genealogist, best known for her 1889 multi-volume work, The Battle Abbey Roll with some Account of the Norman Lineages. As a young woman, she was reputedly the most beautiful woman at court. She was a Maid of Honor at the Queen's coronation and served as a bridesmaid at the Queen's wedding to Prince Albert
Archibald Philip Primrose