At the battle of the Brandywine, he remained on the field after his brigade had been routed, had a horse shot under him, and carried off a piece of ordnance.
On the report of General Washington to Congress, it was ordered that a horse be presented to M. de Fleury "as a mark of the high sense Congress entertained of his merits." (Certified by General Washington and General Sullivan).
N.B. This honour has been paid only to General Arnold and M. de Fleury.
At the battle of Germantown he acted as brigade-major of dragoons, charged several times, and made several prisoners. The horse which had been given to him by Congress was shot under him, and he himself was wounded in the leg. (Certified by General Count Pulaski).
Fort Mifflin, on Mud Island, the only defence of the Delaware, was threatened by the British army and squadron. It was a post of the greatest importance, and M. de Fleury was sent there as chief engineer. He sustained a siege of six weeks behind a stockade. A ship of sixty-four guns, the Augusta, and one of 22 guns, the Merlin, blew up under fire from the fort. The commandant and the garrison, numbering 600 men, were relieved three times, but M. de Fleury refused to leave the fort. He was wounded October 15th, and the fort was evacuated that same night. For this action he was made a lieutenant-colonel, and a letter of thanks was addressed to him by the President of Congress. (Certified by Congress, the General-in-chief, and M. de la Fayette).
During the winter of 1778 he formed the project of crossing the ice and setting fire to the English squadron. The Delaware not being frozen that year hard enough for his purpose, he invented explosive boats, and he was engaged in constructing them when he received orders to join the Army of the North. (Certified by General Washington and Commodore Hasilwood).
The Canadian expedition did not take place, and on his return M. de Fleury was appointed inspector and charged with forming, instructing, and disciplining the troops. (Certified by General Washington).
At the opening of the campaign of 1778 he was second in command of a select corps (in which was the general's body-guard) of 600 men, 2 pieces of ordnance, and 50 cavalry. He served in this capacity at the battle of Monmouth and afterward.
On the arrival of the French squadron, he was sent to meet Count d'Estaing by General Washington, and he went with him to Rhode Island, where an attack was expected.
It was by his advice that the fruitless siege of Newport was raised, and that the retreat to the north part of the island was resolved upon. The corps in which he served repulsed the enemy and covered the retreat. (Certified by General Sullivan).