These constant menaces and movements were exasperating, and Cortés resolved personally to inflict a lesson which might be lasting. At the same time he proposed to complete his reconnoissance of the lake region and encourage his troops with spoils from hostile localities whereon the Aztecs yet relied for support.18
Cortés selected thirty horse, three hundred infantry, a number of Tlascaltecs, and over twenty thousand Tezcucans, under Prince Ixtlilxochitl, to which twice that number of other allies were added on the way.
A large proportion of archers and aquebusiers were taken, together with Alvarado, Olid, Alderete, Melgarejo, and others, while Sandoval was left in charge of Tezcuco, with instructions to watch and promote the completion of the brigantines against which several incendiary attempts had been made.
The expedition left Friday, the 5th of April, and passed through Chalco, Tlalmanalco, and Chimalhuacan,19 and crossing in a south-westerly direction into the Totolapan province, they entered the hills which form the southern border of the Mexican valley.
By this time the forces had assumed proportions hardly inferior to those of the Iztocan campaign, when over one hundred thousand moved against the foe.
Highly picturesque was the spectacle of this army, its naked hordes of warriors relieved by plumage and glittering iztli points which rose above the broad line of gaudy shields; its white adventurers in mail of cotton and metal, surmounted by bright helmets, and armed knights on proudly stepping steeds: picturesque in particular as it wound in almost endless line along the rounded slopes of the cliffs, or climbed in clearly defined file across the hill-tops, only to descend again into gulches gloomy as their own sinister purpose.