The daughter of Sir Charles Cope, second baronet; in 1790 she married John Frederick Sackville, third Duke of Dorset, and upon his death, in 1801 she married the diplomat Charles Whitworth, first Earl of Whitworth.

REFERENCES TO Arabella Diana Sackville, duchess of Dorset [née Cope]:

Eleanor Creevey to Thomas Creevey, 3 November 1805 in The Creevey Papers: A Selection from the Correspondence & Diaries of the late Thomas Creevey, M.P. (London: John Murray, 1903)