[2] After his promotion was confirmed, on 23 April 1726, he served under Gaspard-Joseph Chaussegros de Léry, an engineer employed in the rebuilding of Fort Niagara.
In 1744 War broke out between France and Britain, and in 1746 the French launched a massive counterattack in an attempt to overturn British gains in Acadia.
[3][4][5] On 10 July, he landed with 700 men at Baie Verte in New Brunswick, stationing himself in Beaubassin, he began gathering troops before laying siege to Fort Anne.
[5] Ramezay planned a surprise assault, sending a detachment of 300 men under Captain Nicolas Antoine II Coulon-de-Villiers across the mountains in hostile conditions.
[3] In the spring of 1759 he was given responsibility for defense of the upper town against an expected attack by British forces under Major General James Wolfe.
Ramezay describes in his diary how for two weeks thousands of men, soldiers and sailors, carried, dug and hacked at the earth.
[11] Vaudreuil sent word to Ramezay notifying him of his withdrawal and instructing him to defend the city until "he shall fall short of provisions", at which point he was to select the most capable officer to propose its capitulation.
[11] The British, now in control of the plains, brought up heavy artillery including twelve 24 pound cannons, large mortars and four inch howitzers, with which to bombard the city.
[12] A battery on the opposite shore at Point Levi had already made it impossible for the defenders of the city to remain on its walls[13] and Vice-Admiral Saunders who had hitherto kept his largest ships downstream, now brought seven of the most powerful to join the frigates already in the basin.
[14] The British were keen to settle things quickly before the onset of winter, and this show of strength was to facilitate a prompt surrender.
[14] In summing up, Ramezay declared, "Considering the instructions I have received from the Marquis de Vaudreuil and the scarcity of provisions, proved by the returns to me furnished and the searches I have made, I conclude to endeavour to obtain from the enemy the most honourable capitulation".
[19] Ramezay received some criticism for his actions not least from Vaudreuil and Bougainville[20] but others were quick to defend him; Francois Daine, lieutenant general for civil and criminal affairs at the court of Quebec, wrote a letter to Versailles stating that Ramezay had surrendered in order not to, "...expose the garrison and the people to a general assault, and thereby the fury of the avenger, according to the laws of war".