qnli question: What were reasons that the late 1757 time frame looked bad for Prussia? sentence: First, Frederick devastated Prince Soubise's French force at the Battle of Rossbach on 5 November 1757 and then routed a vastly superior Austrian force at the Battle of Leuthen on 5 December 1757 With these victories, Frederick once again established himself as Europe's premier general and his men as Europe's most accomplished soldiers.