Wriothesly (1708-32), who succeeded his father as 3rd Duke when three years old, revealed a weak, unstable character. His marriage when seventeen to Anne Egerton, a granddaughter of Sarah, 1st Duchess of Marlborough, was a disaster. Frustrated and bored, he took to drink and gambling, which not only caused his death when twenty-four, but also seriously encumbered his estate. He was succeeded as 4th Duke by his brother John (1710-71), who had married Lady Diana Spencer, daughter of Anne Churchill and the Earl of Sunderland, another granddaughter of the formidable Duchess of Marlborough, who thought him ‘much the greatest match in England’. Lady Diana died in 1735. Two years later John married Gertrude Leveson-Gower, generally regarded as proud and insolent, and the union was a great success.
Arthus Foss, The Dukes of Britain (56)