‘A typical battle’

‘The Aztecs were not usually concerned with positional war, or war for the possession of a defined battlefield area unless it served some particular purpose. Their goal was to maneuver the enemy into situations of entrapment and this demanded perfect coordination and timing. The first order of business was to raise a system of battlefield signals. This was achieved by establishing a command post on an adjacent hill with a direct sight line to the army. Signals were sent by relay. Runners were spaced out at two-and-a-half-mile (4km) intervals. Smoke was effective at communicating at longer distances between the xiquipilli [units of 8,000 men], as were “heliographs” made from polished iron pyrite mirrors. When engaging in actual combat, however, commanders relied on the enormous ornamental standards together with conch shell horns and drums.

Conch blower and drummer signal a fierce battle to come... Detail from a Diego Rivera mural, National Palace, Mexico City

‘Hostilities generally opened with a mutual barrage of arrows, darts and sling bullets at 50 yards in an effort to disrupt formations. The Aztecs employed bowmen and slingers from conquered provinces who could be deployed as mobile units either at the front of the line to trigger combat after which they retired to the rear, or directed to the flanks [sides] to lay down harassing fire. Frontline veterans were reliant on their superior armour and heavy, broad shields to withstand the rain of enemy missiles; but sufficient injuries were soon inflicted among the youngest and most lightly armoured troops, so that a charge would soon become a necessity. Aztec war was a running war. The vanguard [front line soldiers] depended on sheer inertia to try to smash through the enemy line, and downhill attacks were considered the most effective. The subsequent impact must have been horrific. Once troops on both sides had recovered, however, they would disperse widely into one-on-one engagements so that they could swing their deadly weapons unhindered.
Slashing and blocking blows with maquahuitl [broadsword] and shield demanded a tremendous expenditure of energy and so men were circulated every 15 minutes in order to keep the centre strong.
Officers kept a sharp eye out for any weaknesses in the enemy’s formation and directed “flying” reserves of veterans to fill gaps among their own men as needed.

Aztec bowmen, Codex Mendoza folio 66 (detail)