Events had occurred at sea which frustrated Napoleon's plan for an attack upon Great Britain. This attack, which in 1797 had been but lightly threatened, had, upon the renewal of war with England in 1803, become the object of Napoleon's most serious efforts. An army was concentrated at Boulogne sufficient to overwhelm the military forces of England, if once it could reach the opposite shore. Napoleon's thoughts were centred on a plan for obtaining the naval superiority in the Channel, if only for the few hours which it would take to transport the army from Boulogne to the English coast. It was his design to lure Nelson to the other side of the Atlantic by a feigned expedition against the West Indies, and, during the absence of the English admiral, to unite all the fleets at present lying blockaded in the French ports, as a cover for the invading armament. Admiral Villeneuve was ordered to sail to Martinique, and, after there meeting with some other ships, to re-cross the Atlantic with all possible speed, and liberate the fleets blockaded in Ferrol, Brest, and Rochefort. The junction of the fleets would give Napoleon a force of fifty sail in the British Channel, a force more than sufficient to overpower all the squadrons which Great Britain could possibly collect for the defence of its shores. Such a design exhibited all the power of combination which marked Napoleon's greatest triumphs; but it required of an indifferent marine the precision and swiftness of movement which belonged to the land-forces of France; it assumed in the seamen of Great Britain the same absence of resource which Napoleon had found among the soldiers of the Continent. In the present instance, however, Napoleon had to deal with a man as far superior to all the admirals of France as Napoleon himself was to the generals of Austria and Prussia. Villeneuve set sail for the West Indies in the spring of 1805, and succeeded in drawing Nelson after him; but, before he could re-cross the Atlantic, Nelson, incessantly pursuing the French squadron in the West-Indian seas, and at length discovering its departure homewards at Antigua (June 13), had warned the English Government of Villeneuve's movement by a message sent in the swiftest of the English brigs. [112] The Government, within twenty-four hours of receiving Nelson's message, sent orders to Sir Robert Calder instantly to raise the blockades of Ferrol and Rochefort, and to wait for Villeneuve off Cape Finisterre. Here Villeneuve met the English fleet (July 22). He was worsted in a partial engagement, and retired into the harbour of Ferrol. The pressing orders of Napoleon forced the French admiral, after some delay, to attempt that movement on Brest and Rochefort on which the whole plan of the invasion of England depended. But Villeneuve was no longer in a condition to meet the English force assembled against him. He put back without fighting, and retired to Cadiz. All hope of carrying out the attack upon England was lost.