Despite his record of defeats, he was able to retain his position. He was able to attain command ahead of the more popular Marshal Browne because of the support of his brother who had significant influence over military appointments. During Austria's Third Silesian War against Prussia (part of the wider Seven Years' War), he commanded the army of the Roman-German Emperor at the Battle of Prague, where he was again defeated by Frederick the Great, king of Prussia, but was able to inflict heavy casualties on the larger Prussian forces. He subsequently defeated a much smaller Prussian army in 1757 at the Battle of Breslau before being completely routed by Frederick the Great at the Battle of Leuthen, which is considered one of Frederick's most brilliant victories. During the battle, he was commander of the Imperial Army as appointed by Maria Theresa.