The first duty upon which the Chevalier was engaged in the capacity of secret agent was to assist in the perfection of a scheme for the invasion of England, devised by the Count de Broglio, approved by the King, whose hatred towards England had greatly intensified since the conclusion of peace, and a task ultimately accomplished to the satisfaction of his Majesty in the face of numerous difficulties. Two persons were selected by de Broglio to effect, in concert, the great work in hand—one, the active agent, was a young officer of Engineers of considerable ability and established reputation, Carlet de la Rosière, who had served during the war, and had been attached for a time as aide-de-camp to the Duke de Broglio. A prisoner of the Prussians, Frederick refused to sanction his exchange. ‘When an officer of distinction is taken,’ said that monarch, ‘he is retained as long as possible.’[101] The other, the passive agent, was de la Rosière’s kinsman, the Chevalier D’Eon. The undertaking was to be completed without the knowledge of any of the King’s ministers, and besides the two named, one other person only was admitted into the secret, according to the King’s will. [Sidenote: SURVEYS FOR THE INVASION OF ENGLAND.] ‘M. Durand,—The Count de Broglio having communicated to me the ideas you have originated as to the more desirable means to be employed for resisting the ambition and arrogance of the English nation, I have approved of the plans he has proposed to me on this subject, and have ordered him to proceed with the work. I have enjoined him not to communicate on the matter with anybody except the Sieur D’Eon and Tercier. But as I am aware of the knowledge you possess with regard to this object, and of the service you can render, I desire to send direct word to you, that you are to work in concert with the Count de Broglio and the Sieur Tercier in all that concerns this affair, and that you will communicate to them all you may find having reference thereto, in the depôt of foreign affairs of which you are in charge. You will continue to maintain the most profound secrecy towards everybody, no matter who, with the exception of the persons named above.[102] LOUIS.’ ‘June 5, 1763.’ Every conceivable precaution was taken to avoid discovery and ensure success, and that de la Rosière might not incur the smallest risk of detection by papers of a compromising character being found about his luggage or person, he was ordered to make his periodical reports orally, if possible, to the Chevalier D’Eon, who was to note and retain them within the inviolable precincts of the Embassy, of which he was the _genius loci_. The King was not indifferent to his own safety. _Louis XV. to M. Tercier._