One of the strongest horses was laden with the richest portion of the crown treasure, but all the rest was abandoned. The gold lay in great heaps.

"Take what you like of it!" Cortez said to his men, "but be careful not to overload yourselves. 'He travels safest, in the dark, who travels lightest.'"

His own veterans took his advice, and contented themselves with picking out a few of the most valuable ornaments; but the soldiers of Narvaez could not bring themselves to leave such treasures behind them, and loaded themselves up with as much gold as they could carry.

Cortez now arranged the order of march. The van was composed of two hundred Spanish foot, and twenty horsemen, under the orders of Gonzalo de Sandoval. The rearguard, with the main body of the infantry and the greater portion of the guns, was commanded by Alvarado and Velasquez de Leon. Cortez himself led the center, which was in charge of the baggage, some of the heavy guns, and the prisoners; among whom were a son and two daughters of Montezuma, Cacama, and the other nobles who had been in prison with him. The Tlascalans were divided among the three corps.

A portable bridge had been prepared for crossing the canals which intersected the causeway; the intention being that it should be laid across a canal, that the army should pass over it, and that it should then be carried forward to the next gap in the causeway. This was a most faulty arrangement, necessitating frequent and long delays, and entailing almost certain disaster. Had three such portable bridges been constructed, the column could have crossed the causeway with comparatively little risk; and there was no reason why these bridges should not have been constructed, as they could have been carried, without difficulty, by the Tlascalans.

At midnight the troops were in readiness for the march. Mass was performed by Father Olmedo; and at one o'clock on July 1st, 1520, the Spaniards sallied out from the fortress that they had so stoutly defended.

Silence reigned in the city. As noiselessly as possible, the troops made their way down the broad street, expecting every moment to be attacked; but even the tramping of the horses, and the rumbling of the baggage wagons and artillery did not awake the sleeping Mexicans, and the head of the column arrived at the head of the causeway before they were discovered. Then, as the advanced guard were preparing to lay the portable bridge across the first opening, some Aztec sentinels gave the alarm.

The priests on the summits of the temples heard their cries, and at once sounded their horns and the huge war drum. Instantly the city awoke, and the silence was succeeded by a roar of sound. The vanguard had scarcely got upon the causeway when canoes shot out upon the lake, and soon a storm of stones and arrows burst upon the column. More and more terrible did it become, as fresh canoes, crowded with the warriors, came up. Many of these pushed up to the causeway itself; and the natives, landing, fell upon the Spaniards with fury.

The latter made no stay. Fighting their way through their foes they pressed on until they reached the next opening in the causeway, and there waited for the bridge to come up. But a column many thousands strong, with baggage and artillery, takes a long time to cross a bridge; and the advanced guard had reached the opening long before the rear had passed the bridge, and there stood helpless, exposed to the terrible storm of missiles, until at last the column were all across the bridge.

Then forty picked men, who had been specially told off for the task, tried to raise it so that it might be carried to the front; but the weight of the baggage wagons and artillery had so wedged it into the earth, that they were unable to move it. They persevered in their efforts until most of them had fallen. The rest bore the terrible news to the army that the bridge was immovable.