
May 21, 1776: Smallpox, Reinforcements, and the Fight for New York as the Revolution Enters a Dangerous New Phase
By May 21, 1776, the American Revolution had entered one of its most uncertain and dangerous periods. The stunning Patriot assault on Quebec the previous winter had failed. Smallpox was devastating the Continental Army in Canada.
Massive British reinforcements were now pouring into North America. General George Washington was racing to prepare New York City for what many believed would become the decisive battlefield of the war. Across the colonies, Americans were still debating the final step toward independence even as the machinery of full-scale war accelerated around them.
Far to the north, the strategic collapse of the American invasion of Canada was becoming undeniable. The British rescue of Quebec, which had begun with the arrival of Royal Navy ships earlier in May, was now expanding into a much larger military buildup along the St. Lawrence River.
On this day, the British corvette Hunter encountered English and Brunswick troops under Major General John Burgoyne moving upriver toward Quebec. More transports followed behind them. British commanders expected Governor General Sir Guy Carleton soon to command nearly 10,000 troops for operations aimed at driving the Continental Army completely out of Canada and reclaiming the northern frontier.
What had begun in 1775 as an ambitious American attempt to bring Canada into the Revolution was collapsing into retreat and disease. The invasion, first launched under Generals Richard Montgomery and Benedict Arnold, had nearly succeeded during the desperate winter assault on Quebec on December 31, 1775.
Montgomery had been killed, Arnold wounded, and the survivors left to maintain a failing siege through one of the harshest winters imaginable. By spring, the Americans were starving, undersupplied, poorly clothed, and increasingly consumed by smallpox.
Now the disease struck the highest level of command. At Sorel on the Richelieu River, Major General John Thomas was forced to relinquish command after contracting smallpox himself. Thomas had only recently taken over the Canadian department from David Wooster after Congress lost confidence in the campaign’s direction.
Instead of inheriting an army capable of renewed operations, he found chaos. Enlistments were expiring, discipline was deteriorating, supplies were dangerously low, and the retreat from Quebec had become increasingly disorganized.
Writing to Brigadier General David Wooster on May 21, Thomas admitted the grim reality. He informed Wooster that he had been “seized with the small pox” and declared that “the safety of the army” required him to leave camp. Command therefore reverted to Wooster at one of the worst possible moments imaginable.
Thomas’s illness symbolized the wider catastrophe unfolding in Canada. Smallpox was one of the greatest killers of the Revolutionary War. Many soldiers had never been exposed to the disease before and lacked immunity.
Camps became breeding grounds for infection. Entire units were weakened or incapacitated. The epidemic affected military planning as much as enemy action did. Within weeks, Thomas himself would die of the disease, becoming the highest-ranking American officer lost to illness during the Revolution.
The failure in Canada carried enormous consequences for the entire war. Congress had hoped the conquest of Quebec might eliminate Britain’s northern base, persuade French Canadians to join the rebellion, and prevent British invasions from the north. Instead, the defeat ensured Canada would remain a British stronghold for the rest of the Revolution and opened the corridor that Burgoyne would later use during the Saratoga campaign of 1777.
While the northern army struggled to survive, General George Washington focused on another looming crisis hundreds of miles to the south. On May 21, Washington departed New York for Philadelphia after receiving Congress’s summons, but before leaving he issued detailed instructions to ensure military preparations continued without interruption.
New York had rapidly become the strategic center of the war. Both Washington and British commanders understood its importance. The city possessed one of the finest harbors in North America and controlled the vital Hudson River corridor connecting New England to the middle colonies. If Britain captured New York and dominated the Hudson, the colonies could potentially be divided in two.
Washington left Major General Israel Putnam in charge of the city’s defenses while Major General Nathanael Greene oversaw extensive fortification work. Earthworks, batteries, redoubts, and defensive lines were being constructed across Manhattan, Long Island, Governor’s Island, and surrounding waterways.
Washington ordered that tools, powder, ammunition, and engineering materials be secured immediately. Coordination with New York’s civil authorities also had to continue as tensions inside the city increased.
The commander in chief was especially concerned about Loyalist activity. New York contained a large population still sympathetic to the Crown, and Washington authorized Putnam and Greene to assist local authorities against “dangerous” or “disaffected” persons if necessary.
Yet he insisted operations be carried out with “secrecy,” “speed,” “order,” and restraint, understanding how fragile civilian support could become if military power was abused.
At the same time, Washington tightened the army’s defensive discipline. Orders issued that day reflected an army preparing for imminent attack. Guards at lines, batteries, and redoubts were carefully assigned. Officers were instructed to inspect men and ammunition at reveille.
Artillery crews, matrosses, and sentries were given precise responsibilities. Lookouts at Fort George and the Battery were specifically warned to keep a “sharp look out” toward the Narrows, Staten Island, and Red Hook for any sign of British ships approaching.
Even small details mattered. Soldiers were warned against careless dry firing that damaged musket flints and were instructed to practice instead with wooden “snappers.” In an army short on supplies, preserving weapons mattered enormously. Washington understood that discipline was no longer abstract military theory. It meant survival.
These preparations came as Americans increasingly realized the war was evolving into something larger than a protest against Parliament. The political center of gravity was moving steadily toward independence.
That same day in Annapolis, Maryland’s provincial convention responded cautiously to Congress’s recent recommendation that colonies suppress royal authority and establish new governments based on popular sovereignty. Maryland’s delegates declared that the people possessed the right to govern their own internal affairs and to raise military force against unconstitutional acts imposed by Parliament.
Yet Maryland stopped short of openly renouncing royal authority altogether. The convention declared that fully suppressing Crown government was “not yet necessary.”
This hesitation reflected the complicated political reality of spring 1776. Many Americans still hoped for reconciliation even while preparing for massive war. Independence was coming, but not all colonies were ready to embrace it at the same pace.
The convention also reelected influential delegates including Samuel Chase, William Paca, Thomas Stone, and Thomas Johnson Jr. to represent Maryland in Congress. Several of these men would later sign the Declaration of Independence only weeks afterward.
Meanwhile, the war at sea continued expanding. At Portsmouth, New Hampshire, shipbuilders launched the Continental frigate Raleigh, one of the ambitious fleet of 13 frigates authorized by Congress in late 1775. Unlike many earlier American warships converted from merchant vessels, Raleigh had been purpose-built for naval combat.
Carrying 32 guns, the frigate represented the growing determination of the Revolution to challenge British naval supremacy, even against overwhelming odds.
The ship’s bow carried a figurehead of Sir Walter Raleigh, the English explorer associated with early English colonization in North America. In a symbolic twist, the rebellion now transformed an icon of English imperial expansion into a symbol of resistance against the British Empire itself.
The Continental Navy was also beginning to protect American commerce more aggressively. On May 21, a convoy moved down the Delaware River from Philadelphia under naval escort.
Captain John Barry’s brigantine Lexington, Lambert Wickes’s Reprisal, and accompanying armed vessels protected merchant shipping against sudden British naval attacks. These convoys became essential lifelines for the revolutionary economy, safeguarding supplies, trade goods, and military matériel.
Off Rhode Island, Captain Nicholas Biddle aboard the Continental brig Andrew Doria demonstrated the growing boldness of American naval operations. After becoming separated from the Cabot during a nighttime alarm involving a vessel believed to be HMS Cerberus, Biddle pursued and captured the sloop Two Friends, bound from Tortola to Liverpool, Nova Scotia.
The captured vessel carried sugar, rum, molasses, and salt, all critically valuable wartime commodities. Biddle placed a prize crew aboard and sent the ship toward Providence while continuing his cruise. Such captures helped sustain the American war effort financially while disrupting British commerce across the Atlantic world.
What makes May 21, 1776, so important in the story of the American Revolution is how clearly it reveals the war entering a new and more dangerous stage. The fighting was no longer centered only around Boston or isolated protests against British taxes.
The Revolution had become continental in scale. Armies maneuvered from Canada to the Caribbean. Disease threatened campaigns as much as battle. Naval warfare spread along the coast. Colonies debated sovereignty even as British reinforcements crossed the Atlantic in enormous numbers.
Within less than two months, Congress would declare independence. Within less than three months, British warships and tens of thousands of troops would descend upon New York in the largest military expedition Britain had ever sent overseas.
The decisions, movements, illnesses, preparations, and warnings of May 21, 1776, were all part of that gathering storm.