In 1777, a French nobleman Marquis de Lafayette, yet to be twenty, joined George Washington's Continental Army and soon became the Commander-in-Chief's trusted aide-de-camp. He saw his first battle in September but the Battle of Brandywine ended in a defeat and Lafayette was wounded himself.
While recuperating at Bethlehem, Lafayette wrote to Marquis de Bouillé, his much elder cousin and Governor of the Windward Islands, and suggested an attack on the British West Indies under the American flag. (France was not at war with Britain at the time.) One recipient of his similar letter remarked that Lafayette would some day strip the palace of Versailles of its furniture for the benefit of "his American cause" (George Morgan, The True Lafayette).
Bouillé forwarded the plan to Versailles but it was not approved (Ebenezer Mack, The Life of Gilbert Motier de Lafayette). Bouillé's reply in March 1778 took a form of an innocuous letter about a real estate purchase.
In the above quotation, the real meaning under the cover text is indicated in brackets. The copy of this letter (in English) in the Papers of Continental Congress comes with its keys, which show the hidden meaning of ten phrases in the order of appearance in the letter. Thus, obviously, the keys were specifically written down for this particular letter.
While this letter advised waiting, France had signed a treaty of alliance with America in February 1778 and actually entered into war with Britain in the summer. Bouillé captured several islands from the British this year (Wikipedia).
The technique used in this letter, known as "open code", is quite common in history. David Kahn, Codebreakers, gives several examples in the twentieth century and a short piece by Alfred Noyes, Uncle Hyacinth (1918) also employs this form. In the eighteenth century, Jacobites frequently adopted the language of trade as a blind to their secret communications (e.g., Earl Stanhope, Reign of Queen Anne Until The Peace of Utrecht).
Lafayette had left France in defiance of the King's orders. His conduct was an embarrassment for the French government because, at the time, France had no intention of being publicly involved with the American cause.
When Lafayette temporarily returned to France in February 1779, he was warmly welcomed by the French court. Now, France was at war with Britain and Lafayette, who had the confidence of George Washington and other American leaders, was an invaluable authority on American affairs.
When he returned to America in April 1780, he had official instructions from Vergennes. From Philadelphia, he sent a packet of letters to Vergennes but the letters were captured by the British and decoded by the Deciphering Branch. The letter of May 20 reported the overall situation as Lafayette saw it and was written in an extensive two-part code. (Kahn p.187)
After taking a part in the Battle of Brandywine and the Battle of Monmouth among others, Lafayette took command in Virginia to check Cornwallis' invasion from the South in 1781. Soon Cornwallis was bottled up in Yorktown, while Lafayette was joined by the combined American and French army of Washington and Rochambeau. When the French fleet under Admiral de Grasse arrived at the Chesapeake, the fate of Cornwallis was sealed. Cornwallis surrendered in October 1781.
While it was not certain at the time that the victory of Yorktown finally decided the war, Lafayette sailed for France on 18 December and was welcomed as a hero.
Although he planned to return to America in a short time, he was asked by American ministers in France to assist them.
At one time, he tried to start correspondence in code with Adams in Holland.
Upon departure for Boston for sailing for France, Lafayette had sent Washington a small list of code numbers of about 50 elements ranging from 1 to 115 (WE088).
During 1782, he occasionally used this code in writing to Washington from France. A section in his letter of 30 March 1782 reads as follows:
On the same day, Lafayette wrote to Livingston about negotiations of peace, French money, and Spain and asked him to communicate its content to Washington.
Lafayette's letter of 12 April again used the code: "I have little to add on one article, but that my expectations are increasing about 47 [Charlestown], but Spain will insist upon 26 [West Indies]." This was written shortly after Lord North resigned and a more sympathetic administration was formed in Britain. However, again, Lafayette reserved details for an encoded letter of the same date to Livingston.
Apparently, Lafayette took care not to tax his dear General with a complex code.
On 14 October, he again communicated intelligence of a secret nature to Livingston and asked him to send the letter to Washington. At the same time, Lafayette requested a colonel Gouvion, a bearer of the letter, to tell Washington "that it is better not to write about my plans, in case of peace, and lest it should give way to ideas in the West Indies." The French court had decided on an expedition under the command of Count d'Estaing and Lafayette had agreed to go as Chief-of-Staff.
In December, Lafayette again spared Washington the details.
In this letter, Lafayette used only one code in saying "We shall have 71 [maritime superiority]."
In the above-mentioned letters of 30 May and 12 April to Livingston, Lafayette used a somewhat fuller code.
The Lafayette-Livingston code is now illustrated with reference to a letter of 25 June. In the manuscript, one passage written in code has an accompanying interlinear translation as follows.
The letter was written in English but the code was for French. The present author succeeded in reconstructing the original French text of the first half of this passage as follows.
The correspondence between the codes and the syllables is as follows.
Syllables in parentheses ( ) are those verified up to variation under polyphonicity by at least one other instance for which plaintext is known, while syllables in brackets [ ] represent guesses.
This Lafayette-Livingston code has a relatively small vocabulary of about 480 elements. It is polyphonic in the sense that the same number may represent several variations of a syllable. For example, "10" may represent "le" or "les" and "353" may represent "ois[ais]" or "oit[ait]". Probably to distinguish those variants, an underline or a double-underline is occasionally used, as in the case for the Livingston-Washington code (see another article).
Livingston, on his part, used the code on 2 November 1782.
While Lafayette was assembling at Cadiz an army of 24,000 French and Spanish troops, news came of a preliminary peace treaty signed on 20 January 1783.
In late 1784, Lafayette again visited America on Washington's invitation.
When leaving for home, he again sent Washington a "small cypher" (WE089).
Lafayette referred to the Department of Foreign Affairs. Livingston had resigned in June 1783 and more than a year's vacancy, John Jay had become the second Secretary of Foreign Affairs.
When Washington received this, he replied that he had Livingston's code (see another article for the Livingston-Washington code).
If Lafayette meant the French code, Washington would have had troubles.
The code Lafayette used in a letter of 11 May 1785 was probably the new small code for Washington. While the complete code list has not been located, 16 code numbers are known. (Weber p. 61) While the numbers range from 12 to 1600, Lafayette called it "a small cypher" and it would not be a full code having 1600 elements. It seems significant that the two known four-digit codes are round numbers: "1400" for "leader" and "1600" for "finances".
In this letter, Lafayette wrote about a dangerous project of relieving the suffering Protestants in France and warned Washington not to answer it. He ventured to mention this only because the letter was carried by John Quincy Adams, who at the same time was also trusted with Jefferson's code THE=812 for Monroe and THE=224 for John Jay (see another article).
After his visit to America in 1784, Lafayette offered great help for Thomas Jefferson, the US minister in France. Lafayette was still popular after the French Revolution broke out and in 1792, when war was declared against Austria, he was given command of an army. But he was not suited as a leader in such a tumultuous age. When the influence of the Jacobins grew, he was replaced and went into exile. In trying to flee to the United States, he was taken by the Austrians and was imprisoned for five years.
While many means were devised for communication for the prisoners, one interesting way used a number of popular songs known in Paris as airs of the Pont Neuf. The songs were so well known that a few notes could recall the words that accompany them (Sholto and Reuben Percy, Percy Anecdotes p.105; Mary MacDermot Crawford, The Wife of Lafayette, Chapter XX; George Morgan, The True Lafayette, p. 387).
In 1797, Lafayette was at last freed by Napoleon. Later in his life, upon invitation of President Monroe, he again visited America in 1824 and grateful Americans received him with "demonstrations of frenzied enthusiasm without precedent or parallel in American history".