In 1812 Napoleon invaded Russia, a traditional ally of Austria. The Austrians were forced by Napoleon to send Schwarzenberg commanding a corps to the Grande Armée. He had to show enough commitment to please Napoleon without angering Russia. In the end he just failed to protect the Grande Armé from a flank attack at the Berezina. But in late November his soldiers withdrew into winter quarters at Byalistok under a verbal agreement with the Russians. 7,000 of his soldiers were killed in battle and 4,000 died of disease and exposure of some 30,000 who had entered Russia, in a disastrous campaign where Napoleon lost 500.000 of 600.000 men.