Basing the military on the nobility meant that rewards also went to the elites. Moreover, the great diversity of weapons among the Maya indicates a lack of centralized control, suggesting the existence of a warrior class that owned its own weapons rather than a centralized army. This diversity also suggests that Maya armies did not rely on formations of uniform-arms wielders; such formations require training and group discipline unlikely to have been imposed on the nobility. Instead, greater emphasis was probably placed on individual prowess and less on group combat. Moreover, with the impetus of social mobility, aristocratic military systems were more resistant to the adoption of mass weapons. There was little incentive to adopt them among the elites, and the commoners, who could have gained from their use, could not participate. In such a system, commoners had little motivation for warfare.

. . . .

Added to the material evidence of professionalization among Teotihuacan’s soldiers was the apparent existence of formal military orders similar to the Aztec’s eagle and jaguar knights. Members of these orders entered battle clad in feather-covered suits (presumably worn over cotton armor) representing eagles, jaguars, coyotes, and so forth. To some extent, these orders may have reflected functional combat divisions: jaguar warriors are most often associated with atlatls and darts whereas eagle warriors favor thrusting spears, but this division was not clearcut in practice and these weapons were used by other military groups as well. Neither is it certain that these orders fought as functional units. They may have served as unit commanders, but since other well-armored soldiers who were not members of these military orders greatly outnumbered the members, the former more likely served in command positions.

How the army was mustered, organized, and controlled is unknown, although the presence of apartment compounds typically housing in excess of a hundred people suggests that these may have been the basic organizational units of Teotihuacan. Teotihuacan’s mean population for the period of A.D. 300-750 was 125,000, potentially yielding an offensive army of almost 16,000 and an effective maximum of almost 27,000. By A.D. 500, Teotihuacan may have reached a peak in excess of 200,000, fielding an offensive army of 25,500 or an effective maximum of 43,000. At the same time, the rest of the Valley of Mexico held an additional army of almost 39,000 men and its effective army to almost 66,000—a force unmatched in Mesoamerica at that time.

. . .

The Aztec army owed much of its success to size. By 1519, Tenochtitlan held at least 150,000-200,000 people and estimates of the valley-wide population range from 1,000,000-1,200,000 to 2,200,000-2,650,000. This would have yielded an offensive army of 25,250 from Tenochtitlan, drawing on all males between twenty and thirty, and an effective maximum army of 43,000 drawing on all males between twenty and fifty. For the Valley of Mexico as a whole, the offensive army would have been 151,5000 to 334,563 with a maximum effective army of 258,480 to 570,810. In practice, however, the Aztec mobilization was proportional to the perceived threat. If the threat was small, only the elite troops would be summoned, as they were always available. If the threat was greater, additional men were summoned through the ward herdman. And if the threat was very large, additional forces were drawn from allied towns in the surrounding area.