British Prime Minister William Pitt's focus on the colonies for the 1758 campaign paid off with the taking of Louisbourg after French reinforcements were blocked by British naval victory in the Battle of Cartagena and in the successful capture of Fort Duquesne and Fort Frontenac. The British also continued the process of deporting the Acadian population with a wave of major operations against Île Saint-Jean (present-day Prince Edward Island), the St. John River valley, and the Petitcodiac River valley. The celebration of these successes was dampened by their embarrassing defeat in the Battle of Carillon (Ticonderoga), in which 4,000 French troops repulsed 16,000 British.

How did the British assure numerical superiority in taking Louisbourg?