On the fifth of April he began his march, and on the following day arrived at Chalco, where he was met by a number of the confederate chiefs. With the aid of his faithful interpreters, Doña Marina and Aguilar, he explained to them the objects of his present expedition, stated his purpose soon to enforce the blockade of Mexico, and required their co-operation with the whole strength of their levies. To this they readily assented; and he soon received a sufficient proof of their friendly disposition in the forces which joined him on the march, amounting, according to one of the army, to more than had ever before followed his banner.1
Taking a southerly direction, the troops, after leaving Chalco, struck into the recesses of the wild sierra, which, with its bristling peaks, serves as a formidable palisade to fence round the beautiful Valley; while within its rugged arms it shuts up many a green and fruitful pasture of its own. As the Spaniards passed through its deep gorges, they occasionally wound round the base of some huge cliff or rocky eminence, on which the inhabitants had built their towns, in the same manner as was done by the people of Europe in the feudal ages; a position which, however favorable to the picturesque, intimates a sense of insecurity as the cause of it, which may reconcile us to the absence of this striking appendage of the landscape in our own more fortunate country.
The occupants of these airy pinnacles took advantage of their situation to shower down stones and arrows on the troops as they defiled through the narrow passes of the sierra. Though greatly annoyed by their incessant hostilities, Cortés held on his way, till, winding round the base of a castellated cliff occupied by a strong garrison of Indians, he was so severely pressed that he felt to pass on without chastising the aggressors would imply a want of strength which must disparage him in the eyes of his allies. Halting in the Valley, therefore, he detached a small body of light troops to scale the heights, while he remained with the main body of the army below, to guard against surprise from the enemy.