On December 19, the Americans followed suit and entered winter quarters at Valley Forge; while Washington's domestic opponents contrasted his lack of battlefield success with Gates' victory at Saratoga, foreign observers such as Frederick the Great were equally impressed with Germantown, which demonstrated resilience and determination. Over the winter, poor conditions, supply problems and low morale resulted in 2,000 deaths, with another 3,000 unfit for duty due to lack of shoes. However, Baron Friedrich Wilhelm von Steuben took the opportunity to introduce Prussian Army drill and infantry tactics to the entire Continental Army; he did this by training "model companies" in each regiment, who then instructed their home units. Despite Valley Forge being only twenty miles away, Howe made no effort to attack their camp, an action some critics argue could have ended the war.