Lady Cecilia Maria Charlotte Molyneux was born in 1838, the daughter of Charles William Molyneux, 3rd Earl of Sefton and Mary Augusta née Gregg-Hopwood. On 12 July 1869 she married Hugh Richard Dawnay, 8th Viscount Downe. The marriage produced five children. In 1897 her husband became 1st Baron of Danby and subsequently sat in the House of Lords.