Episode 024

Spying During the Revolutionary War – Part I

There have been TV series and movies that centered around covert activities or spying during the Revolutionary War. What actually happened that you should be aware of?

Before we begin I want to say that this has been one of my favorite episodes to research and record thus far. The whole idea of the Intelligence community and spying during the Revolutionary War is fascinating, and I’m only really scratching the surface and hitting the highlights here. If you’re interested, I’ve added a few spy books in the Recommended Reading section

To start our conversation, we need to go back a year, almost to the day, from our last episode to September of 1775. The Second Continental Congress was in session and felt the need to, and subsequently created a Secret Committee by a resolution on September 18, 1775. The Committee was not, however, a true intelligence agency, since the Committee of Secret Correspondence with which it often worked was mainly concerned with obtaining military supplies in secret and distributing them, and selling gunpowder to privateers chartered by the Congress. The Committee also took over and administered on a uniform basis the secret contracts for arms and gunpowder previously negotiated by certain members of the Congress without the formal sanction of that body. The Committee kept its transactions secret and destroyed many of its records to ensure the confidentiality of its work.

The Secret Committee employed agents overseas, often in cooperation with the Committee of Secret Correspondence. It gathered intelligence about secret Loyalist ammunition stores and arranged to seize them. The Committee also sent missions to seize British supplies in the southern colonies. It arranged the purchase of military stores through intermediaries to conceal the fact that Congress was the true purchaser. They then used foreign flags to attempt to protect the vessels from the British fleet.

The members of the Continental Congress appointed to the Committee included some of the most influential and responsible members of Congress: Benjamin Franklin, Robert Morris, Robert Livingston, John Dickinson, Thomas Willing, Thomas McKean, John Langdon, and Samuel Ward.

Recognizing the need for foreign intelligence and foreign alliances, the Second Continental Congress created the Committee of Correspondence (soon renamed the Committee of Secret Correspondence) by a resolution of November 29, 1775:

Those resolutions read as follows:

RESOLVED, That a committee of five would be appointed for the sole purpose of corresponding with our friends in Great Britain, and other parts of the world, and that they lay their correspondence before Congress when directed;

RESOLVED, That this Congress will make provision to defray all such expenses as they may arise by carrying on such correspondence, and for the payment of such agents as the said Committee may send on this service.

The original Committee members—America’s first foreign intelligence agency—were Benjamin Franklin, Benjamin Harrison, and Thomas Johnson. Subsequent appointees included James Lovell, a teacher who had been arrested by the British after the battle of Bunker Hill on charges of spying. He had later been exchanged for a British prisoner and was elected to the Continental Congress. On the Committee, he became the Congress’ expert on codes and ciphers and has been called the father of American cryptanalysis.

By far the most active member of the Committee of Secret Correspondence was Benjamin Franklin. Franklin, a successful scientist, journalist, and politician was an expert when it came to foreign affairs.He sent letters to Don Gabriel de Bourbon, a Spanish Prince, and American supporters in France to try to rally support for the American cause. He also travelled to France to convince the French to forge an alliance with the United States and was a prominent figure in the signing of the Treaty of Paris in 1783, which ended the revolution.

The committee employed secret agents abroad, conducted covert operations, devised codes and ciphers, funded propaganda activities, authorized the opening of private mail, acquired foreign publications for use in analysis, established a courier system, and developed a maritime capability apart from that of the Continental Navy, and engaged in regular communications with Britons and Scots who sympathized with the American cause.

Since the Committee of Secret Correspondence put much of its efforts into gaining patriot sympathy abroad to be used during the American Revolution, they requested of the Continental Congress that the members and actions of the committee be kept confidential, so that Great Britain would not hear about the United States forging foreign alliances for the looming revolution. Another reason the Committee wanted its members and actions kept quiet was because the committee had many undercover agents on missions overseas gaining information about the political and economic situation in other countries, and if other countries heard about these undercover agents they would be exposed and their missions ruined. For example, in 1776, the Committee was instructing Silas Deane, an undercover agent in France, on how to interact with the French government and encourage them to provide munitions and ships to the United States.

In response to this request for secrecy, Congress did several things. First of all, Congress agreed to the “withholding the names of the persons they [the Committee of Secret Correspondence] has employed, or with whom they have corresponded.” In addition, Congress recorded all of the decisions regarding the Committee of Secret Correspondence in “Secret Journals”, separate from the public journals used to record its decisions concerning other matters. Finally, it allowed the committee to establish its own oath of secrecy, which was put in place on November 29, 1775 as well as a secrecy agreement for government employees.

On April 17, 1777, the Committee of Secret Correspondence was renamed the Committee of Foreign Affairs but kept with its intelligence function. Matters of diplomacy were conducted by other committees or by the Congress as a whole. On January 10, 1781, the Department of Foreign Affairs—the forerunner of the Department of State—was created and tasked with “obtaining the most extensive and useful information relative to foreign affairs”, the head of which was empowered to correspond “with all other persons from whom he may expect to receive useful information.”

Committee on Spies

On June 5, 1776, the Congress appointed John Adams, Thomas Jefferson, Edward Rutledge, James Wilson, and Robert Livingston

“to consider what is proper to be done with persons giving intelligence to the enemy or supplying them with provisions.”

They were charged with revising the Articles of War in regard to espionage directed against the American forces. The problem was an urgent one: Dr. Benjamin Church, chief physician of the Continental Army, had already been seized and imprisoned as a British agent, but there was no civilian espionage act, and George Washington thought the existing military law did not provide punishment severe enough to afford a deterrent. On November 7, 1775, the death penalty was added for espionage to the Articles of War, but the clause was not applied retroactively, and Dr. Church escaped execution.

In case you are unfamiliar, the Articles of War were drawn up as a set of 69 rules that govern what you can and can do during war…aka…rules of warfare. The US Military justice system continued to operate under the same Articles of War (with a few minor changes) until 1951 when the Uniform Code of Military Justice came into effect.

On August 21, 1776, the Committee’s report was considered by the Congress, which enacted the first espionage act:

RESOLVED, That all persons not members of, nor owing allegiance to, any of the United States of America, as described in a resolution to the Congress of the 29th of June last, who shall be found lurking as spies in or about the fortification or encampments of the armies of the United States, or of any of them, shall suffer death, according to the law and usage of nations, by sentence of a court martial, or such other punishment as such court martial may direct.

It was resolved further that the act “be printed at the end of the rules and articles of war.” On February 27, 1778, the law was broadened to include any “inhabitants of these states” whose intelligence activities aided the enemy in capturing or killing revolutionary forces.

RESOLVED, That every member of this Congress considers himself under the ties of virtue, honour and love of his country, not to divulge, directly or indirectly, any matter or thing agitated or debated in Congress, before the same shaft have been determined, without the leave of the Congress: nor any matter or thing determined in Congress, which a majority of the Congress shall order to be kept secret, And that if any member shall violate this agreement, he shall be expelled this Congress, and deemed an enemy to the liberties of America, and liable to be treated as such, and that every member signify his consent to this agreement by signing the same.

On June 12, 1776, the Continental Congress adopted the first secrecy agreement for employees of the new government. The required oath read:

“I do solemnly swear, that I will not directly or indirectly divulge any manner or thing which shall come to my knowledge as (clerk, secretary) of the board of War and Ordnance for the United Colonies. . . So help me God.”

The Continental Congress, sensitive to the vulnerability of its covert allies, respected their desire for strict secrecy. Even after France’s declaration of war against England, the fact of French involvement prior to that time remained a state secret. When Thomas Paine, in a series of letters to the press in 1777, divulged details of the secret aid from the files of the Committee of Foreign Affairs (formerly, the Committee of Secret Correspondence), France’s Minister to the United States, Conrad Alexandre Gerard, protested to the president of the Congress that Paine’s indiscreet assertions “bring into question the dignity and reputation of the King, my master, and that of the United States.” Congress dismissed Paine, and by public resolution denied having received such aid, resolving that “His Most Christian Majesty, the great and generous ally of the United States, did not preface his alliance with any supplies whatever sent to America.”

In 1779, George Washington and John Jay, the president of the Continental Congress and a close associate of the Commander in Chief’s on intelligence matters, disagreed about the effect disclosure of some intelligence would have on sources and methods. Washington wanted to publicize certain encouraging information that he judged would give “a certain spring to our affairs” and bolster public morale. Jay replied that the intelligence “is unfortunately of such a Nature, or rather so circumstanced, as to render Secrecy necessary.” Jay prevailed.


Robert Townsend, an important American agent in the British-occupied city of New York, used the guise of being a merchant, as did Silas Deane when he was sent to France by the Committee of Secret Correspondence. Townsend was usually referred to by his cover name of “Culper, Junior.” When Major Benjamin Tallmadge, who directed Townsend’s espionage work, insisted that he disengage himself from his cover business to devote more time to intelligence gathering, General Washington overruled him:

“it is not my opinion that Culper Junior should be advised to give up his present employment. I would imagine that with a little industry he will be able to carry on his intelligence with greater security to himself and greater advantages to us, under the cover of his usual business. . .. it prevents also those suspicions which would become natural should he throw himself out of the line of his present employment.”

Townsend also was the silent partner of a coffee house frequented by British officers, an ideal place for hearing loose talk that was of value to the American cause.

Major John Clark’s agents in and around British-controlled Philadelphia used several covers (farmer, peddler, and smuggler, among others) so effectively that only one or two operatives may have been detained. The agents traveled freely in and out of Philadelphia and passed intelligence to Washington about British troops, fortifications, and supplies, and of a planned surprise attack.

Enoch Crosby, a counterintelligence officer, posed as an itinerant shoemaker (his civilian trade) to travel through southern New York state while infiltrating Loyalist cells. After the Tories started to suspect him when he kept “escaping” from the Americans, Crosby’s superiors moved him to Albany, New York, where he resumed his undercover espionage.

John Honeyman, an Irish weaver who had offered to spy for the Americans, used several covers (butcher, Tory, British agent) to collect intelligence on British military activities in New Jersey. He participated in a deception operation that left the Hessians in Trenton unprepared for Washington’s attack across the Delaware River on December 26, 1776.


In January 1778, Nancy Morgan Hart, who was tall, muscular, and cross-eyed, disguised herself as a “touched” or emotionally disturbed man, and entered Augusta, Georgia, to obtain intelligence on British defenses. Her mission was a success. Later, when a group of Tories attacked her home to gain revenge, she captured them all and was witness to their execution.

In June 1778, General Washington instructed Henry “Light Horse Harry” Lee to send an agent into the British fort at Stony Point, New York, to gather intelligence on the exact size of the garrison and the progress it was making in building defenses. Captain Allan McLane took the assignment. Dressing himself as a country bumpkin and utilizing the cover of escorting a Mrs. Smith into the fort to see her sons, McLane spent two weeks collecting intelligence within the British fort and returned safely.

Secret writing

While serving in Paris as an agent of the Committee of Secret Correspondence, Silas Deane is known to have used a heat-developing invisible ink—a compound of cobalt chloride, glycerine and water—for some of his intelligence reports back to America. Even more useful to him later was a “sympathetic stain” created for secret communications by James Jay, a physician and the brother of John Jay. Dr. Jay, who had been knighted by George III, used the “stain” for reporting military information from London to America. Later he supplied quantities of the stain to George Washington at home and to Silas Deane in Paris.

The stain required one chemical for writing the message and a second to develop it, affording greater security than the ink used by Deane earlier. Once, in a letter to John Jay, Robert Morris spoke of an innocuous letter from “Timothy Jones” (Deane) and the “concealed beauties therein,” noting

“the cursory examinations of a sea captain would never discover them, but transferred from his hand to the penetrating eye of a Jay, the diamonds stand confessed at once.”

Washington instructed his agents in the use of the “sympathetic stain,” noting in connection with “Culper Junior” that the ink

“will not only render his communications less exposed to detection, but relieve the fears of such persons as may be entrusted in its conveyance.”

Washington suggested that reports could be written in the invisible ink “on the blank leaves of a pamphlet. . . a common pocket book, or on the blank leaves at each end of registers, almanacks, or any publication or book of small value.”

Washington especially recommended that agents conceal their reports by using the ink in correspondence: “A much better way is to write a letter in the Tory stile with some mixture of family matters and between the lines and on the remaining part of the sheet communicate with the Stain the intended intelligence.”

Even though the Patriots took great care to write sensitive messages in invisible ink, or in code or cipher, it is estimated that the British intercepted and decrypted over half of America’s secret correspondence during the war, but this estimation has never been fully backed up by data.

Codes and ciphers

American Revolutionary leaders used various methods of cryptography to conceal diplomatic, military, and personal messages.

John Jay and Arthur Lee devised dictionary codes in which numbers referred to the page and line in an agreed-upon dictionary edition where the plaintext (unencrypted message) could be found.

In 1775, Charles Dumas designed the first diplomatic cipher that the Continental Congress and Benjamin Franklin used to communicate with agents and ministers in Europe. Dumas’s system substituted numbers for letters in the order in which they appeared in a preselected paragraph of French prose containing 682 symbols. This method was more secure than the standard alphanumeric substitution system, in which a through z are replaced with 1 through 26, because each letter in the plain text could be replaced with more than one number.

The Culper Spy Ring used a numerical substitution code developed by Major Benjamin Tallmadge, the network’s leader. The Ring began using the code after the British captured some papers indicating that some Americans around New York were using “sympathetic stain.” Tallmadge took several hundred words from a dictionary and several dozen names of people or places and assigned each a number from 1 to 763. For example, 38 meant attack, 192 stood for fort, George Washington was identified as 711, and New York was replaced by 727. An American agent posing as a deliveryman transmitted the messages to other members of the Ring. One of them, Anna Strong, signaled the message’s location with a code involving laundry hung out to dry. A black petticoat indicated that a message was ready to be picked up, and the number of handkerchiefs identified the cove on Long Island Sound where the agents would meet. By the end of the war, several prominent Americans—among them Robert Morris, John Jay, Robert Livingston, and John Adams—were using other versions of numerical substitution codes.

The Patriots had two notable successes in breaking British ciphers. In 1775, Elbridge Gerry and the team of Elisha Porter and the Rev. Samuel West, working separately at Washington’s direction, decrypted a letter that implicated Dr. Benjamin Church, the Continental Army’s chief surgeon, in espionage for the British.

In 1781, James Lovell, who designed cipher systems used by several prominent Americans, determined the encryption method that British commanders used to communicate with each other. When a dispatch from Lord Cornwallis in Yorktown, Virginia, to General Henry Clinton in New York was intercepted, Lovell’s cryptanalysis enabled Washington to gauge how desperate Cornwallis’s situation was and to time his attack on the British lines. Soon after, another decrypt by Lovell provided warning to the French fleet off Yorktown that a British relief expedition was approaching. The French scared off the British flotilla, sealing victory for the Americans.

Like This Episode?

What are your thoughts? Discuss below...

Free Updates by Email

Get show updates and notes directly in your email inbox!