Having finally completed the preparation of the materials for his brigantines, he sent a strong convoy to transport them to Tezcuco. The Tlascalans furnished him 8,000 _tamanes_, or carriers, and appointed 15,000 warriors to accompany the Spanish troops. The materials were carried sixty miles across the mountains, and finally reached Tezcuco in safety.
A new reinforcement of soldiers, with horses, battering cannon, and ammunition, now also joined him from Hispaniola, whither he had sent to raise recruits. The brigantines were soon finished; for the purpose of floating them into the lake, a canal, two miles long, was made by deepening a small rivulet, and amid shouts, firing of cannon, and religious ceremonies, they were launched.
The force, destined for this final attack on Mexico, amounted to 86 horsemen and 818 foot-soldiers, of whom 118 were armed with muskets or crossbows; a train of artillery of three battering cannon, and fifteen field pieces. Each brigantine was manned by twenty-five Spaniards, and bore one of the small cannon. These Cortés commanded in person. The points selected for the attack were, from Tepejacac on the north side of the lake, from Tacuba on the west, and Cojohuacan towards the south, corresponding to the causeways which have been heretofore mentioned. By cutting off the aqueducts, the inhabitants were reduced to great distress; and the efforts of the Mexicans to destroy the fleet were entirely unsuccessful.
Cortés, now master of the lake, pushed on his attack from all points, broke down the barricades, forced his way over the trenches, and sought to penetrate into the heart of the city. The Mexicans, though losing ground every day, repaired the breaches by night, laboring with incredible effort to recover their posts. With his small force, the Spaniard dared not attempt a lodgment where he might be hemmed in by numbers, and thus defeated. Finally, however, his troops, by the most desperate assaults, penetrated into the city; a success which was shortly turned into a disastrous and nearly fatal defeat, in consequence of the commander of one of the divisions, Juan de Alderete, neglecting his instructions to fill up the canals and gaps in the causeways, as he proceeded, in order to secure the means of retreat.