Charles-Geneviève-Louis-Auguste-André-Timothée d'Éon de Beaumont (October 5, 1728 - May 21, 1810), usually known as the Chevalier d'Éon, was a French diplomat, spy, soldier and Freemason who lived the first half of her life as a man and the second half as a woman.
In 1761, d'Éon returned to France. The next year she became a captain of dragoons under the Marshal de Broglie and fought in the later stages of the Seven Years' War. She was wounded and received the Order of Saint-Louis.
In 1763 d'Éon became plenipotentiary minister in London and used this position also to spy for the king. She collected information for a potential invasion. She formed connections with English nobility by sending them the produce of her vineyards. When she was about to lose the post of plenipotentiary, she complained, and eventually decided to disobey orders to return to France. In her letter to the king, she claimed that the new ambassador had tried to drug her. In an effort to save her station in London, she published most of the secret diplomatic correspondence about her recall under the title Lettres, mémoires, et négociations in 1764.
When France began to help the rebels during the American War of Independence, d'Éon asked to be able to join French troops in America. He was jailed below the castle of Dijon for 19 days, and spent the following six years with her mother in Tonnerre.
In 1779 d'Éon published her memoirs La Vie Militaire, politique, et privée de Mademoiselle d'Eon. They were ghostwritten by a friend named La Fortelle, and are probably embellished.
D'Éon returned to England in 1785. She lost her pension after the French Revolution and had to sell her library. In 1792 she sent a letter to the French National Assembly, offering to lead a division of women soldiers against the Hapsburgs, but the offer was rebuffed. She participated in fencing tournaments until she was seriously wounded, in 1796. In 1805 she signed a contract for an autobiography, but the book was never published. She spent her last years with a widow, Mrs. Cole.
The Chevalier d'Éon died in London. Doctors who examined her after death discovered that her body was anatomically male. However, it is possible that she had Kallmann syndrome, a hormonal disorder in which a person's body does not go through puberty. This is suggested by the fact that no known portraits of the Chevalier show her with any facial hair - even the portrait of her death mask, which was cast at the time of her death in 1810. It should be noted, however, that it was highly unusual for fashionable gentlemen of the 18th century to sport any facial hair.
The term Eonism was coined to refer to similar cases of transgender behavior, but is now little used because of its ambiguity.
An alternative, but inaccurate, account is offered by some associated with the transvestite community, in which the life of the Chevalier d'Eon is different.
Instead of claiming to be born a woman, Beaumont was an effeminate but definitely male member of the court of Louis XV, who was selected to act as a female diplomat to the court of Elizabeth of Russia. This was done in order to persuade the Russian government to admit Jacques-Joachim Trotti, marquis de La Chétardie – an attempt which was successful. Beaumont was then appointed as the (male) ambassador to Russia, where he was forced to live a double life, acting the parts of both himself and his "sister", "Lia".
Fearing the charade was to be uncovered, he was then dispatched to the English court, where he maintained the double life.
On the death of Louis XV, Beaumont attempted to blackmail Louis XVI by revealing his activities. It is claimed that instead of imprisoning Beaumont, the new monarch decreed that Beaumont could return to France only if he lived permanently as a woman. It is further claimed that Beaumont occasionally appeared at the French court in male attire, only to be forcibly dressed in women's clothing.