Eon De Beaumont
EON DE BEAUMONT, Charles Geneviève Louise Auguste André Timothée d' (1728-1810), commonly known as the Chevalier d'Eon, French political adventurer, famous for the supposed mystery of his sex, was born near Tonnerre in Burgundy, on the 7th of October 1728. He was the son of an advocate of good position, and after a distinguished course of study at the Collège Mazarin he became a doctor of law by special dispensation before the usual age, and adopted his father's profession. He began literary work as a contributor to Fréron's Année littéraire, and attracted notice as a political writer by two works on financial and administrative questions, which he published in his twenty-fifth year. His reputation increased so rapidly that in 1755 he was, on the recommendation of Louis François, prince of Conti, entrusted by Louis XV. (who had originally started his "secret" foreign policy - i.e. by undisclosed agents behind the backs of his ministers - in favour of the prince of Conti's ambition to be king of Poland) with a secret mission to the court of Russia. It was on this occasion that he is said for the first time to have assumed the dress of a woman, with the connivance, it is supposed, of the French court.  In this disguise he obtained the appointment of reader to the empress Elizabeth, and won her over entirely to the views of his royal master, with whom he maintained a secret correspondence during the whole of his diplomatic career. After a year's absence he returned to Paris to be immediately charged with a second mission to St Petersburg, in which he figured in his true sex, and as brother of the reader who had been at the Russian court the year before. He played an important part in the negotiations between the courts of Russia, Austria and France during the Seven Years' War. For these diplomatic services he was rewarded with the decoration of the grand cross of St Louis. In 1759 he served with the French army on the Rhine as aide-de-camp to the marshal de Broglie, and was wounded during the campaign. He had held for some years previously a commission in a regiment of dragoons, and was distinguished for his skill in military exercises, particularly in fencing. In 1762, on the return of the duc de Nivernais, d'Eon, who had been secretary to his embassy, was appointed his successor, first as resident agent and then as minister plenipotentiary at the court of Great Britain. He had not been long in this position when he lost the favour of his sovereign, chiefly, according to his own account, through the adverse influence of Madame de Pompadour, who was jealous of him as a secret correspondent of the king. Superseded by count de Guerchy, d'Eon showed his irritation by denying the genuineness of the letter of appointment, and by raising an action against Guerchy for an attempt to poison him. Guerchy, on the other hand, had previously commenced an action against d'Eon for libel, founded on the publication by the latter of certain state documents of which he had possession in his official capacity. Both parties succeeded in so far as a true bill was found against Guerchy for the attempt to murder, though by pleading his privilege as ambassador he escaped a trial, and d'Eon was found guilty of the libel. Failing to come up for judgment when called on, he was outlawed. For some years afterwards he lived in obscurity, appearing in public chiefly at fencing matches. During this period rumours as to the sex of d'Eon, originating probably in the story of his first residence at St Petersburg as a female, began to excite public interest. In 1774 he published at Amsterdam a book called Les Loisirs du Chevalier d'Eon, which stimulated gossip. Bets were frequently laid on the subject, and an action raised before Lord Mansfield in 1777 for the recovery of one of these bets brought the question to a judicial decision, by which d'Eon was declared a female. A month after the trial he returned to France, having received permission to do so as the result of negotiations in which Beaumarchais was employed as agent. The conditions were that he was to deliver up certain state documents in his possession, and to wear the dress of a female. The reason for the latter of these stipulations has never been clearly explained, but he complied with it to the close of his life. In 1784 he received permission to visit London for the purpose of bringing back his library and other property. He did not, however, return to France, though after the Revolution he sent a letter, using the name of Madame d'Eon, in which he offered to serve in the republican army. He continued to dress as a lady, and took part in fencing matches with success, though at last in 1796 he was badly hurt in one. He died in London on the 22nd of May 1810. During the closing years of his life he is said to have enjoyed a small pension from George III. A post-mortem examination of the body conclusively established the fact that d'Eon was a man.
The best modern accounts are in the duc de Broglie's Le Secret du roi (1888); Captain J. Buchan Telfer's Strange Career of the Chevalier d'Eon (1888); Octave Homberg and Fernand Jousselin, Le Chevalier d'Eon (1904); and A. Lang's Historical Mysteries (1904).
 But see Lang's Historical Mysteries, pp. 241-242, where this traditional account is discussed and rejected.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)