The British also hoped that taking the well-known fort would boost troop morale and honour after their demoralizing battle defeat at Fort Ticonderoga  in July 1758. In August 1758, the British under the command of Lieutenant-Colonel John Bradstreet left Fort Oswego with a force of a little over 3000 men and attacked Fort Frontenac. The fort's garrison of 110 men, commanded by Pierre-Jacques Payen de Noyan et de Chavoy, surrendered and were allowed to leave. Bradstreet captured the fort's supplies and nine French naval vessels, and destroyed much of the fort. He quickly departed to avoid further conflict with any French support troops. For the British, Fort Oswego was secured, and the army's reputation was restored.  For the French, the fort's loss was considered to be only a temporary setback.'Fort Frontenac's surrender did not succeed in completely severing French communications and transportation to the west since other routes were available . Supplies could also be moved west from other French posts .  In the long term, however, the surrender compromised French prestige among the Indians and contributed to the defeat of New France in North America. Since the fort was no longer perceived to be important to the French, it was never rebuilt and was left abandoned for the next 25 years. French imperial power was waning in the late 1750s, and by 1763 France had withdrawn from the North American mainland.  Cataraqui and the remains of Fort Frontenac were relinquished to the British.. How many months after their defeat at Fort Ticonderoga  did the British attack Fort Frontenac?