Despite the large build-up of British forces in North America, the strategy of dividing the army for separate attacks on Canada meant that once Wolfe reached Quebec the French commander Louis-Joseph de Montcalm would have a local superiority of troops having raised large numbers of Canadian militia to defend their homeland. The French had initially expected the British to approach from the east, believing the St Lawrence River was impassable for such a large force, and had prepared to defend Quebec from the south and west. An intercepted copy of British plans gave Montcalm several weeks to improve the fortifications protecting Quebec from an amphibious attack by Wolfe.