1745 Fortress Louisbourg surrenders
To secure their hold on their North American colonies the French built an impressive fortress on the Cape Breton peninsula in what is now Nova Scotia. Designed by the Marquis de Vauban, Louis XIV’s military engineer, the fort with its ditches, thick walls, and cannon looked impregnable.
In 1744, Britain was drawn into conflict with France as part of the larger War of the Austrian Succession. The Anglo-French clash would be known in the British colonies as King George’s War. Until this time, Louisbourg had not participated in any military actions, although the fortress had provided refuge for Indigenous people allied with the French who raided English settlements. Louisbourg also offered a safe harbour for French privateers who preyed on fishing fleets and ships from New England.
On 24 May 1744, a force of soldiers from Louisbourg aboard a fleet of 17 vessels, under the command of Captain François du Pont Duvivier, made a surprise attack on the small English fort and settlement at Grassy Island, near Canso (on the present-day Nova Scotia mainland), forcing the British garrison there to surrender. The French destroyed the settlement and took the British to Louisbourg as prisoners. While the British awaited transfer to Boston in a prisoner exchange, their officers were free to move about the town. They took note of weaknesses in the so-called “impregnable” fortress.
In Boston, the freed officers reported their observations to Massachusetts governor William Shirley. They told him that Louisbourg’s garrison was undermanned, and that morale among the French troops was low, largely because of poor food and because they hadn’t been paid in months. They also said that due to poor construction, parts of the seemingly formidable walls were crumbling. They also revealed the presence of nearby ridges and hills overlooking Louisbourg’s landward walls. And they made sketches of Louisbourg’s defences, which they gave to Shirley.
Shirley raised a force of more than 4,000 New Englanders, commanded by William Pepperell, for an expedition against Louisbourg. The colonial army would be supported by a Royal Navy squadron under Commodore Peter Warren. In April 1745, Pepperell established a base at Canso, where he met with Warren in early May to plan a land and sea operation.
The first siege of Louisbourg began on 11 May 1745. Pepperell had captured strategic points near the fortress, and Warren’s ships blockaded the harbour. The colonial army used sledges to haul artillery across marshy ground to high points from which the guns could bombard the town and batter the walls. The French warship Vigilant carrying vital supplies and reinforcements, was captured by Warren’s squadron. By 16 June, Louisbourg’s walls had been breached and Warren’s fleet was poised to enter the harbour. Short of supplies and ammunition, and under pressure from the town’s merchants to capitulate, French governor Louis DuPont Duchambon surrendered.
Arrangements were made for most of the population to be transported to France. Warren was promoted to rear admiral, and Pepperell was rewarded by Britain with a baronetcy. Under the terms of the Treaty of Aix-la-Chapelle of 1748, the British returned Louisbourg, and all of Île Royale, to the French, much to the disgust of the New Englanders, who considered it an act of betrayal by the British government.