The sitter was the daughter of Colonel Hervey Bagot of Pipe Hall, Warwickshire, and his wife Dorothy, daughter and co-heir of Sir Henry Arden. On 18th December, 1664 she married Charles Berkeley, later the Earl of Falmouth, who was described by Pepys as 'a witty man in every respect but of no good character'. He was killed on board the Royal Charles fighting the Dutch in Southwold Bay in 1665. Their only child Mary, married Gilbert Gerard. The sitter's second marriage was to Charles Sackville, Earl of Middlesex and Dorset, Knight of the Garter, and Lord Lieutenant of Sussex from 1670 to his death in 1691. He is described by Bishop Burnet as being of 'great learning', and was a patron of Dryden, Wycherly, and Prior. The Countess of Middlesex died on 12th September, 1679. Pepys called her 'a pretty woman and pleasant in her looks', and De Gramont was even more lavish in his praise, describing her as 'the only one who was really possessed of virtue and beauty among these maids of honour'.