Fears reached their peak during the winter of 1777. While Howe’s army lived comfortably in Philadelphia, Washington’s army retreated 20 miles to Valley Forge, where 12,000 soldiers and hundreds of camp followers suffered horribly. “The army … now begins to grow sickly,” a surgeon confided to his diary. “Poor food — hard lodging — cold weather — fatigue — nasty clothes — nasty cookery. … Why are we sent here to starve and freeze?” Nearby farmers refused to help. Some were pacifists, Quakers and German sectarians unwilling to support either side. Others looked out for their own families, selling grain for gold from British quartermasters but refusing depreciated Continental currency. “Such a dearth of public spirit, and want of public virtue,” lamented Washington. By spring, more than 200 officers had resigned, 1,000 hungry soldiers had deserted, and another 3,000 had died from malnutrition and disease. That winter at Valley Forge took as many American lives as had two years of fighting.

In this dark hour, Baron von Steuben raised the readiness of the American army. A former Prussian military officer, von Steuben was one of a handful of republican-minded foreign aristocrats who joined the American cause. Appointed as inspector general of the Continental army, he instituted a strict drill system and encouraged officers to become more professional. Thanks to von Steuben, the smaller army that emerged from Valley Forge in the spring of 1778 was a much tougher and better-disciplined force.