Nevertheless, Pitt wielded the amphibious might of Britain with a master hand. Sea-power, mercantile and naval, enabled him to 'command the riches of the world' and become the paymaster of many thousand Prussians under Frederick the Great and Ferdinand of Brunswick. He also sent a small British army to the Continent. But he devoted his chief attention to working out a phase of the 'Maritime War' which included India on one flank and the Canadian frontiers on the other. Sometimes with, and sometimes without, a contingent from the Army, the British Navy checkmated, isolated, or defeated the French in Europe, Asia, Africa, and America. The preliminary isolation of Louisbourg was a particularly effective stroke of naval strategy. Even before 1758 began the first French fleet that left for Louisbourg had been shadowed from Toulon and had been shut up in Cartagena. A second French fleet was then sent to help the first one out. But it was attacked on the way and totally defeated. In April the first fleet made another attempt to sail; but it was chased into Rochefort by Hawke and put out of action for the rest of the campaign. The third French fleet did manage to reach Louisbourg. But its admiral, du Chaffault, rightly fearing annihilation in the harbour there, and wishing to keep some touch between Old France and New, sailed for Quebec with most of his best ships. Quebec and the rest of Canada were themselves on the defensive; for Abercromby was leading 15,000 men--the largest single army America had ever seen--straight up the line of Lake Champlain. Montcalm defeated him at Ticonderoga in July. But that gave no relief to Louisbourg; because the total British forces threatening the Canadian inland frontier were still quite strong enough to keep the French on the strict defensive.