December 23, 1777 dawned cold and dank over the hills of Valley Forge, Pennsylvania, the scent of snow in the air. General George Washington, pacing the headquarters tent of his revolutionary army’s winter encampment, was dictating a testy ultimatum to the Continental Congress, laced with what he called his “infinite pain and concern.”

On his mind? British troop advancement and the dire state of his forces. As he spoke, some 12,000 troops were setting up camp around him for the winter, cobbling together 2,000 or so rude huts with foraged wood and the barest of tools. Horses and oxen were in such short supply that the men were reduced to yoking themselves to makeshift carts. Many soldiers went without coats, shoes and blankets; most ate little in the way of meat. That day in camp, there were no cattle to slaughter and fewer than 30 barrels of flour in the commissary. The upshot: Nearly 3,000 freezing, near-naked and starving troops—a quarter of Washington’s force—had been declared unfit for duty.

The six months that the Continental Army would spent at Valley Forge would be the most difficult, and ultimately, transformative of the American Revolution. That December, at a nadir in his campaign to expel the British, Washington found himself in a desperate moment, one that drove him to consider one of his boldest, and riskiest, military maneuvers yet: a Christmas Eve attack.

Washington’s dispatch to the Congress that morning flagged a crisis situation: The British General Sir William Howe was on the move that very day, with a force of more than 8,000 Redcoats and Hessians. Having ventured out of the then-capital city of Philadelphia (which they captured three months earlier), they had crossed the Schuylkill river and, according to Continental scouts, were headed to raid nearby farmsteads for hay and livestock. But with the British force now positioned less than 20 miles south of Valley Forge, Washington worried that Gen. Howe would fill his forage wagons and then turn north to overrun his own ragtag, depleted army.

“I ordered the Troops to be in rediness [for an attack] but behold!,” Washington wrote to what was left of the Congress, “to my great mortification…the Men were unable to stir on Acct. of Provision. All i could do under these circumstances was, to send out a few light Parties to watch and harass the Enemy."

Washington blamed the civilian authorities for the wretched state of affairs. He was convinced “beyond a doubt” that if the Continental Congress and the Pennsylvania state legislators did not rapidly comply with his multiple requests for food, clothes, medicine, and blankets, “unless some great and capital change suddenly takes place in the [supply] line, this Army must inevitably be reduced to one or other of these three things. Starve, dissolve, or disperse, in order to obtain subsistence in the best manner they can.”

Starve, dissolve or disperse. It was the gauntlet thrown. How low Washington and his army had fallen in a mere 12 months.

When the Continental Congress named George Washington head of the nascent United States Army in 1775 and charged him with throwing off the shackles of the greatest empire on earth, the tall Virginian had discontinued keeping a personal journal lest it fall into enemy hands. We are thus left with only the writings of his closest aides for glimpses of Washington’s innermost thoughts and feelings over eight years of war. As Christmas approached during that dismal winter at Valley Forge two years after his appointment, one of those aides, the 33-year-old Philadelphian Tench Tilghman, certainly echoed the General’s nostalgia for a much happier holiday only one year earlier.

“I wish we could put [the British] in mind…of what happened this time twelvemonth,” Tilghman wrote to one of Washington’s commanding generals. And, indeed, it is difficult to overestimate the impact the previous year’s Christmas raids on Trenton and Princeton had on the psyche and morale of the Continental Army and its Commander in Chief. Not even the resounding defeats Americans had suffered across the intervening months—at Brandywine Creek, at Paoli, at Germantown, at the Forts Mifflin and Mercer—could dull the luster of that marvelous memory.

Nor was it lost on Washington that the most glorious celebration of the anniversary would be to replicate his Trenton and Princeton victories on a larger scale. Hence, another surprise attack began to cohere in George Washington’s mind.

He intended to begin the assault with a ruse. On Christmas Eve, he confided to his trusted friend General John Sullivan, he envisioned a portion of the “light Parties” which had been shadowing Gen. Howe’s movements would fall on the left flank of the British column as if they were the point movement of a major attack. Washington assumed Gen. Howe would naturally attempt to quick-time the bulk of his force back to Philadelphia while leaving several detachments to screen his retreat and cover the Schuylkill’s northern fords.

Then, while the 6,000 Crown troops who remained in Philadelphia under the command of the Hessian Gen. Wilhelm von Knyphausen rushed to cover Howe’s fallback, a Continental shock corps of some 4,000 men advancing in two columns—between 50 and 60 men and eight officers drawn from each regiment—would dash south to capture the British ramparts north of the city. Once these battlements were taken, the right column of Americans would rush south along the Schuylkill to seize the four ferry crossings and destroy any temporary bridges, stranding Howe’s rump army on the west bank of the river and cutting him off from von Knyphausen. Howe and his troops, their backs to the Schuylkill, would be left with no choice but to surrender or be swept into the river.

Yet even if Washington viewed the battle plan as “a work which depends more upon secrecy and dispatch than Numbers,” it nonetheless flew in the face of a hard-and-fast military dictate of the era—that is, an attacking force should always be at least double the size of the defenders. Moreover, the daunting metrics only complicated the scheme. A victorious outcome, after all, hung not only on Washington’s correct reading of Howe’s tactical thinking, but upon several and various moving parts all working in conjunction—a set of tumblers clicking into place and locking the Continental Army into a commitment that might well end the war...or, conversely, destroy the revolution.

Instead of convening a war council to discuss the engagement, Washington decided to put out feelers to a small coterie of his most trusted officers via Gen. Sullivan, the former governor of New Hampshire. Within hours, he returned to Washington’s tent headquarters with their decidedly tepid reactions. The generals saw the reality of the Continental Army’s destitute condition perhaps better than the Commander in Chief. Several cautioned that only if the British were to move on Valley Forge would such a major battle be worth the risk. Others preferred bypassing Philadelphia altogether and instead concentrating an all-out assault on Howe’s foraging party, which would not only sever the Redcoats’ escape route across the Schuylkill, but block any reinforcements pouring out of the city.

Gen. Nathanael Greene of Rhode Island was perhaps the most frank. He knew well the near-messianic fervor with which Washington sought to drive the British from Philadelphia, no matter how well hidden behind the façade of executive sobriety. But he reminded his Commander in Chief about the danger of “consulting our wishes rather than our reason.”

In the end, Washington heeded their advice and decided to stand down. It was, as the Washington biographer Ron Chernow put it, “sometimes better to miss a major opportunity than barge into a costly error.”

The dearth of documentation regarding this Christmas Eve attack makes it difficult to discern just how serious the Commander in Chief was about the proposal. Some historians argue that Washington viewed the Continental Army as in such dire straits that he was willing to risk its survival on long odds rather than see the force disintegrate from a lack of food and supplies.

Others, more conspiracy-minded, suggest that he viewed an attack on Philadelphia as an ultimate make-or-break political moment. The enemy’s presence in America’s capital city was an affront to his own personal honor and reputation, and an assault would result in either a stunning victory or a catastrophic defeat that would shock the Continental Congress into finally recognizing his army’s acute distress.

Still others, such as historian Wayne Bodle, wonder if the “sugar-plum reveries” of Washington’s battle plan were an outgrowth of nostalgia for the glories of Trenton enhanced by “a holiday-induced overindulgence in hemp or Madeira at Headquarters.” For the record, there is no indication that marijuana had filtered into the winter camp.

As the aborted battle plan disappeared into the churn of history on that afternoon of December 23, 1777, a heavy snow began to blanket Valley Forge. It would continue for three days, the worst blizzard of the season thus far. It was during this Christmas whiteout that Washington transferred his headquarters to a small fieldstone cottage hard by the confluence of the Schuylkill and Valley Creek, not far from where he had pitched his headquarters tent. While his personal guard began construction of their own crude huts nearby, Washington, his staff and their servants moved in. On any given day, 18 to 25 people squeezed into the cramped and musty quarters that for the next six months would serve as the de facto capital of the United States.

Two days later, on Christmas afternoon, the ashen-faced troops of the Continental Army filed from their half-built huts and tattered tents like weakened animals emerging from their burrows to receive a holiday dinner of burnt mutton and watery grog. Many, their own feet wrapped in rags, hunched past barefoot sentries standing on their hats in the deepening snow.

Washington and his aides spent the evening picking over a “simple, frugal, and austere” repast of sinewy mutton and hickory nuts. The snow continued to fall. There was no Madeira, much less hemp.

That night, a Continental soldier from Connecticut’s 7 Regiment known to posterity only as Jethro was found dead in his tent. His skin was as cold as the dirt floor on which he lay, and a crude autopsy attributed his passing to a combination of malnutrition and exposure. Jethro’s was the initial death recorded on the rolls at Valley Forge—the first of many. That Jethro was one of the hundreds of freed black men at the winter encampment who had enlisted to fight for the cause of American liberty injects an even more tragic note into his demise.

Incredibly, the worst of that winter at Valley Forge—what the Pulitzer Prize-winning historian Joseph Ellis calls “the existential moment in the war for American independence”—still lay ahead. Many, not least George Washington, wondered if his bobtailed and bloodied army, freezing and starving and seemingly on the verge of “dissolving,” would even exist when the spring campaign began. For the moment, what Washington did not realize—what he could not realize on that Christmas Day—was that in the months to come the deprivations of Valley Forge would anneal his fighting men into a force that would emerge to topple an empire.

Bob Drury and Tom Clavin are the New York Times-bestselling authors of several books, including The Heart of Everything That Is and, more recently, Valley Forge.

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