The fighting was now commenced with greater fury, and prodigies of valor were performed by the Spaniards; but all to no purpose. Another attempt was made to induce the enemy to come to terms. The only answer was the threat that they would all be sacrificed to the gods, and the appalling information, 'You cannot escape; the bridges are broken down.' At last, as death was before their eyes, it was determined by Cortez, and all the officers and soldiers, to quit the city during the night as they hoped at that time to find the enemy less alert.
Towards midnight, on the 1st of July 1520, they left their quarters secretly, most of the soldiers loading themselves with the gold which remained over and above the royal share, and proceeded as silently as possible towards the western causeway leading to Tlacopan, by which, as being the shortest of the three (two miles long), they thought it would be the easiest to effect a passage. In this causeway there were three drawbridges, separated by intervals nearly equal; and aware that these had been destroyed by the Mexicans, Cortez had provided a portable bridge, made of timber, the carriage of which he intrusted to forty picked soldiers. The van of the army was led by Sandoval, with two hundred foot and a body of horse under his command; the baggage, large guns and prisoners came next, guarded by Cortez and a band of veterans; and the rear was brought up by Pedro de Alvarado and Valasquez de Leon, commanding the strength of the infantry.
The night was dark and rainy. The Spaniards reached the causeway without being interrupted. The portable bridge was laid across the first moat or gap, and a great part of the army had gone over it in safety, and were already approaching the second gap, when, through the stillness of the night, there was heard the boom of the great drum from the top of the Mexican war temple, the rushing of myriads of pursuers along the causeway from behind, and the splashing of the oars of thousands of canoes full of warriors, which were advancing through the lake on both sides of the causeway. Showers of arrows fell on the rearguard as they were passing over the portable bridge; and the Aztecs, clambering up the sides of the causeway, grappled with the soldiers, and tried to drag them into the water. Throwing off these assailants by main strength, Alvarado and his men steadily and expeditiously moved on. Meanwhile the vanguard under Sandoval having reached the second gap, were waiting until the portable bridge should be brought up to enable them to cross it. Goaded with the arrows which were discharged upon them in clouds from the Aztec canoes, they grew impatient of the delay, and began to cast anxious glances backward along the causeway for the appearance of the bridge. Suddenly the appalling news was passed along that the bridge had stuck so fast at the first opening that it could not be pulled up. The weight of the men and heavy baggage crossing it had fastened it into the earth so firmly as to defy extrication. When this awful intelligence reached the vanguard, order and command were at an end; uproar and confusion ensued; and, seized with the instinct of self-preservation, each man tried to shift for himself. Flinging themselves headlong into the gap, they struggled with the Mexican warriors in the water, upsetting their canoes in their drowning agonies. Rank after rank followed, each trampling upon the bodies of its predecessors, and floundering among the canoes which lay between them and the opposite side. Sandoval and a few of the cavalry swam their horses across;
