Portrait of Lord Robert Bertie (1721-82), half-length, in armour with a red ermine-trimmed cloak, in a feigned oval; and Portrait of Lady Robert Bertie (1719-98), half-length, in a white dress, blue sash and blue ermine-trimmed robes, in a feigned oval

General Lord Robert Bertie was the fifth son of Robert Bertie, 1st Duke of Ancaster and the third son by the Duke's second wife Albinia Farrington. Bertie joined the Coldstream Guards as ensign in 1737; over the next four decades he rose steadily through the ranks and was promoted to General in 1777. In 1745 he inherited his mother’s estate at Chislehurst in Kent. Beyond his military successes, Bertie also held the illustrious position of Lord of the Bedchamber to the Prince of Wales, later King George III, from 1751 until his death. He sat in Parliament for Whitchurch from 1751 to 1754 and for Boston from 1754 until his death in 1782.

In 1762 Bertie married Mary, youngest daughter of Montague Blundell, 1st Viscount Blundell (see lot 127) and Mary Chetwynd (see lot 128), following her first marriage to Robert Raymond, 2nd Baron Raymond, which ended after Mary was widowed in 1765. Mary was close to her great-niece and goddaughter, Mary, Marchioness of Downshire, who moved in with Lord and Lady Bertie after her own parents died. The Berties' marrriage was without issue and Mary, Marchioness of Downshire, became the sole Blundell heir. There is some confusion with the identifying inscriptions as Mary's sister-in-law, the Duchess of Ancaster, was also called Mary Bertie.