Guatemozin, the son-in-law of Montezuma, was then, by the unanimous acclaim of his countrymen, placed upon the throne. He was a young man of high reputation for ability and force of character, and proved himself the worthy leader of his nation in this dreadful crisis of its fate. Guatemozin assembled all his forces in the capital, as the strongest point upon which they could stand upon their defense. Cortez decided to make the assault by three divisions of the army, each marching over one of the causeways. Sandoval was to command on the north, Alvarado on the west, and Olid on the south. Cortez reserved to himself the command of the brigantines, which were to sweep the lakes, and drive the war-canoes of the natives from the causeways. Each brigantine was manned with twenty-five Spaniards, and armed with a cannon, whose shot would make fearful havoc among the frail and crowded canoes of the Mexicans. Guatemozin immediately foresaw how much he had to dread from this fleet, and decided that, at every hazard, he must attempt its destruction. He accordingly assembled an enormous mass of canoes, hoping by numbers to overpower the enemy. The day was calm; not a ripple disturbed the glassy surface of the water, when a fleet of canoes, in numbers which could not be counted, pushed out boldly into the lake to assail the brigantines lying at anchor. But just then, to the great joy of the Spaniards and to the dismay of the Mexicans, a fresh and favorable breeze arose, which would drive the brigantines resistlessly through the swarm of fragile boats which were approaching them. The sails were instantly spread, the cannon were loaded almost to the muzzle, and the work of death began. The heavy vessels crushed the canoes, overturned them, drove them one upon another in indescribable confusion, while the merciless shot pierced bones, and nerves, and sinews, and the surface of the lake was covered with the mutilated bodies of the dying and of the dead. The water was red with blood, and in a short time the fleet was destroyed; but few of the boats escaped. The Mexicans, from their house-tops, gazed with dismay upon this awful scene of carnage, and were oppressed with fearful forebodings that no degree of courage and no superiority of numbers could avail them against the terrible engines of destruction which European skill had framed. Cortez was now completely master of the lake. He formed his brigantines into three divisions, to cover the assailants on the three causeways and to protect them from any attack by canoes. He thus also preserved communication, prompt and effective, between the different divisions of his army. The military skill displayed by Cortez in all these arrangements is of the highest kind. The conquest of Mexico was not achieved by accident, but by sagacity, persevering energy, and patient toil almost unparalleled.