Mary Osborne, Duchess of Leeds, born Lady Mary Godolphin, was a daughter of Henrietta Godolphin, née Churchill, 2nd Duchess of Marlborough, and Francis Godolphin, 2nd Earl of Godolphin, making her granddaughter to the powerful government trio during the reign of Queen Anne of Great Britain: the famous general and politician John Churchill, 1st Duke of Marlborough, and his wife Sarah, Duchess of Marlborough, through her mother; and Sidney Godolphin, 1st Earl of Godolphin, through her father.
Career
Lady Mary was considered to be the illegitimate child of the famous playwright William Congreve, with whom Henrietta, Duchess of Marlborough, was having a long-term relationship. They had one surviving child, Francis Godolphin Osborne (styled Marquess of Carmarthen, later 5th Duke of Leeds and Secretary of State for Foreign Affairs), who was born on 29 January 1751. Mary, Duchess of Leeds, died in 1764, aged 41.
