CHASSIN DE THIERRY, FRANÇOIS-NICOLAS DE (he signed Thierry de Chassin), officer in the colonial regular troops; b. at Versailles, France, son of Nicolas de Chassin, billeting officer for the king’s household, and Charlotte Thyerry; m. 26 Dec. 1734 at Louisbourg, Île Royale (Cape Breton Island), Marie-Josephe, daughter of Pierre Rousseau de Souvigny and Jeanne de Saint-Étienne de La Tour, by whom he had six children; d. 20 Oct. 1755 at Louisbourg.

François-Nicolas de Chassin de Thierry first came to Canada in 1717 as a cadet and returned to France the following year. In 1719 he was posted to Louisiana as a second lieutenant. Following a grave illness in 1725, he returned to France in the spring of 1726 to convalesce. He remained there until the spring of 1730 when he was appointed ensign at Île Royale. He was promoted lieutenant in 1737 and captain in 1744.

Thierry’s service at Louisbourg apparently met with the approval of his superiors. In 1732 the governor of Île Royale, Saint-Ovide [Monbeton], charged him with supervising the annual assembly of the Indians of Nova Scotia and Île Royale; he was entrusted “with the presents for the savages and the goods with which to provide a feast.” Of his performance Saint-Ovide reported: “one cannot be more satisfied than I was with the exactness, the devotion, and the care which this officer showed during the course of the journey.”

Thierry is best remembered as the officer responsible for the hasty evacuation of Louisbourg’s Royal battery on the night of 11 May 1745, shortly after New Englanders under the command of William Pepperrell landed at Gabarus Bay. In a terse note to the commandant, Louis Du Pont* Duchambon, Thierry had claimed that the battery was virtually impossible to defend against a landward assault and should therefore be evacuated and blown up. At a tumultuous meeting of the council of war, all the officers present, except Étienne Verrier, the engineer, concurred with Thierry’s recommendation. Finally a compromise was reached: the battery would be abandoned but not destroyed, its guns would be spiked and its stores of foodstuffs and munitions evacuated to Louisbourg. Once the order was transmitted, Thierry’s men proceeded in uncontrolled panic, driving steel rods into the guns’ touch holes, but neglecting to smash either trunnions or carriages, and leaving virtually all the stores behind in their flight into Louisbourg. On 12 May a detachment was sent out to carry away the foodstuffs and powder, but the shells and ball were left behind.

Meanwhile, detachments of New Englanders began pouring onto the high ground which dominated the walled fortress on three sides. Early on 13 May William Vaughan of New Hampshire discovered that the Royal battery had been abandoned and promptly proceeded, “with y^e grace of God and y^e courage of about thirteen men,” to take possession. Within 24 hours New England armourers had unspiked the battery’s guns and had them trained on Louisbourg. The anonymous “Habitant” noted in his Journal: “From the fourteenth, the enemy saluted us with our own guns and kept up a tremendous fire.”

In this way Thierry provided “mighty Encouragement and Advantage” to the inexperienced New Englanders. The defenders eventually surrendered the fortress on 28 June and the French garrison was evacuated to France. It is perhaps amusing to note that as early as 1750 Thierry was posted once again to command a detachment at the scene of his first effort at soldiering in 1745. Four years later, with over 35 years in the service, he was received into the order of Saint-Louis. He died at Louisbourg a year later.

Bernard Pothier

AN, Col., B, 54, ff.503–3v; 65, ff.482–83; 78, f.410; 93, f.235; 98, f.178; 99, f.249; C^11B, 12, f.270v; 29, ff.39–44, 66–71v; F³, 50; Marine, C⁷, 320 (dossier Thierry de Chassaing); Section Outre-Mer, G¹, 406 (26 déc. 1734); 409 (7 sept., 20 oct. 1755, 5 févr. 1758). Louisbourg in 1745 (Wrong), 39–41. “The Pepperrell papers,” Mass. Hist. Soc. Coll., 6th ser., X (1899). Thomas Prentice, A sermon preached at Charlestown, on a general thanksgiving, July 18, 1745, for the reduction of Cape-Breton . . . (Boston, 1745). Frégault, François Bigot, I. McLennan, Louisbourg, 150–52. Parkman, Half-century of conflict, II. Rawlyk, Yankees at Louisbourg, 89–97.