While the army lay at Valley Forge, the Baron Steuben arrived in camp. This gentleman was a Prussian officer, who came to the United States with ample recommendations. He was said to have served many years in the armies of the great Frederick; to have been one of the aids de camp of that consummate commander; and to have held the rank of lieutenant general. He was, unquestionably, versed in the system of field exercise which the king of Prussia had introduced, and was well qualified to teach it to raw troops. He claimed no rank, and offered to render his services as a volunteer. After holding a conference with congress, he proceeded to Valley Forge. [Sidenote: General Conway resigns. Duel between him and General Cadwallader.] [Sidenote: The Baron Steuben appointed inspector general.] Although the office of inspector general had been bestowed on Conway, he had never entered on its duties; and his promotion to the rank of major general had given much umbrage to the brigadiers, who had been his seniors. That circumstance, in addition to the knowledge of his being in a faction hostile to the Commander-in-chief, rendered his situation in the army so uncomfortable, that he withdrew to York, in Pennsylvania, which was then the seat of congress. When the expedition to Canada was abandoned, he was not directed, with Lafayette and De Kalb, to rejoin the army. Entertaining no hope of being permitted to exercise the functions of his new office, he resigned his commission about the last of April, and, some time afterwards, returned to France.[100] On his resignation, the Baron Steuben, who had, as a volunteer, performed the duties of inspector general, much to the satisfaction of the Commander-in-chief, and of the army, was, on the recommendation of General Washington, appointed to that office with the rank of major general, without exciting the slightest murmur. [Footnote 100: General Conway, after his resignation, frequently indulged in expressions of extreme hostility to the Commander-in-chief. These indiscretions were offensive to the gentlemen of the army. In consequence of them, he was engaged in an altercation with General Cadwallader, which produced a duel, in which Conway received a wound, supposed for some time to be mortal. While his recovery was despaired of, he addressed the following letter to General Washington. _Philadelphia, July 23d, 1778._ Sir,--I find myself just able to hold the pen during a few minutes, and take this opportunity of expressing my sincere grief for having done, written, or said any thing disagreeable to your excellency. My career will soon be over, therefore, justice and truth prompt me to declare my last sentiments. You are, in my eyes, the great and good man. May you long enjoy the love, veneration, and esteem of these states, whose liberties you have asserted by your virtues. I am with the greatest respect, sir,