Soon after the beginning of the Seven Years' War, through the influence of Madame de Pompadour, he was put in command of a corps of 24,000 men, and in November 1757 he sustained the crushing defeat of Rossbach.
Tak lama kemudian dimulai Perang Tujuh Tahun, melalui pengaruh Madame de Pompadour, ianbertanggung jawab atas jiwa 24,000 orang, dan pada bulan Nopember 1757 ia menahan pecahnya kekalahan Rossbach.