In 1757 he reluctantly assumed the command of the army commissioned to rescue Hanover from the threatened invasion of the French. His opponent was Marshal D’Estrées, from before whom he fell back at the Rhine, and to whom he disgracefully surrendered Hanover, by the infamous convention of Klosterseven. When the King saw him enter Kensington Palace, after his peremptory recall, the monarch exclaimed, ‘Behold the son who has ruined me and disgraced himself!’ That son, who declared he had written orders for all he did, and who certainly was invested with very full powers, resigned all his posts; and the hero of Dettingen and pacificator of North Britain became a private gentleman, and took to dice, racing, and other occupations natural then, or common at least, to gentlemen with more money than sense or principle. There is a good trait remembered of him at this period of his career. He had dropped and lost his pocket-book at Newmarket; and declined to make any more bets, saying that ‘he had lost money enough for that day.’ In the evening the book was brought to him by a half-pay officer who had picked it up. ‘Pray keep it, sir,’ said the duke, ‘for if you had not found it, the contents would, before this, have been in the hands of the blacklegs.’ Another favourable trait was his desire to give commissions to men who earned them on the field. He felt that while any ‘fool’ might purchase a commission, it was hard to keep it back from the man who had fought for it. He once promoted a sergeant to an ensigncy, and, finding him very coolly treated by his brother officers, the duke refused to dine with Lord Ligonier unless--pointing to the ensign--he might bring his ‘friend’ with him. This recognition settled the question.