The Nine Years' War was professionally and personally frustrating for the Prince. Initially fighting on the Rhine with Max Emmanuel—receiving a slight head wound at the Siege of Mainz in 1689—Eugene subsequently transferred himself to Piedmont after Victor Amadeus joined the Alliance against France in 1690. Promoted to general of cavalry, he arrived in Turin with his friend the Prince of Commercy; but it proved an inauspicious start. Against Eugene's advice, Amadeus insisted on engaging the French at Staffarda and suffered a serious defeat—only Eugene's handling of the Savoyard cavalry in retreat saved his cousin from disaster. Eugene remained unimpressed with the men and their commanders throughout the war in Italy. "The enemy would long ago have been beaten," he wrote to Vienna, "if everyone had done their duty." So contemptuous was he of the Imperial commander, Count Caraffa, he threatened to leave Imperial service.