Spencer family
The Duke holds subsidiary titles: "Marquess of Blandford" (created in 1702 for John Churchill), "Earl of Sunderland" (created in 1643 for the Spencer family), "Earl of Marlborough" (created in 1689 for John Churchill), "Baron Spencer" of Wormleighton (created in 1603 for the Spencer family), and "Baron Churchill" of Sandridge (created in 1685 for John Churchill), all in the Peerage of England.