The Government had now decided that it would be wise to change the plan of campaign which had so far been followed in the war. General Taylor's army, which had invaded Mexico from the Rio Grande, though it was victorious at Monterey, and later at Buena Vista, could hardly hope to penetrate into the heart of the country without great loss of time, troops, and money. It was resolved to take a shorter route to the interior and so decide the war. General Scott was to command the army of invasion, and Vera Cruz was the point selected for the beginning of its march. By the middle of February the transports containing General Scott's army began to rendezvous at the island of Lobos, and storeships to arrive at Anton Lizardo with materials for the expedition, including sixty-seven surf-boats in which the troops were to be landed. The preparation for the landing was made by the squadron, still under Commodore Conner's command, with such despatch and thoroughness that though General Scott and his staff only arrived on the 6th of March, on the 9th the army was disembarked. Early on the morning of this day the men-of-war, with the troops on board, sailed from their anchorage to Sacrificios, an island just south of Vera Cruz, and by ten o'clock that night the whole body of twelve thousand men had been landed without mishap or loss. No opposition was made to the landing, though the position offered great advantages for defence. A line of investment five miles in length was drawn about the city, and the erection of batteries was begun at once, the naval forces being still employed in landing munitions of war. By the 22d some of the batteries were ready, and the city having refused to surrender, General Scott opened the bombardment. On the day before the attack began, Commodore Conner, who had long been in bad health, and who would have done more wisely to give up the command before, was relieved by Commodore Perry. As the heavy guns provided by the army for the siege--the battering train--had not arrived, the army had only its mortars and a few light guns. These had no effect upon the walls and bastions of the city, and General Scott suggested to Commodore Perry that he should land some of the heavy cannon from the ships. Perry answered that he would land the guns, and moreover that he would fight them. Six heavy guns, each weighing three tons, were landed, and, drawn by two hundred seamen and volunteers, they were moved during the night of the 23d three miles from the landing-place to their position in battery, seven hundred yards from the city wall. On the morning of the 24th they opened, and immediately drawing upon themselves the concentrated fire of the fortifications, they did more real execution than all the batteries which had been hitherto engaged.