They had been retreating for days, bleeding and exhausted, when the Aztec army found them on the plain of Temalcatitlan. It was July 7, 1520, barely a week after La Noche Triste -- the "Night of Sorrows" -- when Hernan Cortes and his forces had fled Tenochtitlan under cover of darkness, losing more than 800 Spanish soldiers and an unknown number of Tlaxcalan allies as Mexica warriors attacked them on the causeways. The survivors who stumbled onto the plain near Otumba were fewer than 500 men at arms, wounded, stripped of most of their gunpowder and gold, harassed by skirmishers for every kilometer of their retreat toward Tlaxcala. The Aztec leadership had resolved to finish them off. What happened next would change the course of the conquest.
To understand Otumba, you have to understand what came before it. In March 1519, Cortes had landed at Potonchan on the Mexican coast with a commission from Cuba's Governor Diego Velazquez de Cuellar -- a commission Velazquez then revoked. Cortes launched his expedition anyway. Through force and political maneuvering, he secured alliances with the Totonacs and the Tlaxcaltec, then marched his force into the heart of the Aztec Empire. When the Spanish entered Tenochtitlan in November 1519, Moctezuma II received them as guests. The situation deteriorated rapidly. Velazquez sent Panfilo Narvaez to bring Cortes to heel; Cortes defeated Narvaez and absorbed his troops, but while he was away, his lieutenant Pedro de Alvarado had attacked an Aztec ceremonial gathering. The Mexica rose in fury. By late June 1520, the Spanish were trapped in a hostile city, Moctezuma was dead, and escape was the only option.
The Aztec force waiting on the plain near Otumba vastly outnumbered the retreating Spanish and Tlaxcalan column. According to Bernal Diaz del Castillo, the conquistador whose firsthand account remains the most detailed record of the battle, the Mexica saw the Spanish as already defeated. Their objective was not simply to kill but to capture -- prisoners taken alive could be sacrificed to the Aztec gods, conferring religious glory on their captors. This focus on capture rather than outright slaughter may have given the Spanish a narrow tactical opening. The Castilian cavalry charged first, breaking through the Aztec ranks and creating gaps for the rodeleros -- sword-and-shield infantry -- and Tlaxcalan foot soldiers to exploit. But the sheer number of Aztec warriors threatened to overwhelm the column regardless.
Cortes had instructed his men to strike at enemy commanders and standards. In the chaos of battle, he spotted the Aztec high priest and military leader Matlatzincatl, identifiable by his elaborate armor, feathered headdress, and the war standard -- the pamitl -- he carried. Cortes understood Mesoamerican battlefield convention: an army whose standard fell and whose commander died would lose its will to fight. He communicated the plan to his captains and led the charge himself, followed by Gonzalo de Sandoval, Pedro de Alvarado, Cristobal de Olid, Juan de Salamanca, and Alonso Davila. Cortes struck Matlatzincatl with his lance. His captains broke the ranks of warriors surrounding the commander. When Matlatzincatl fell and Juan de Salamanca seized the pamitl and delivered it to Cortes, the Aztec forces disengaged. The battle was over.
Otumba was not a conquest -- it was a survival. The Spanish reached Tlaxcala, their allied territory, where they could finally rest, tend their wounded, and begin rebuilding the force that La Noche Triste had shattered. Over the following year, Cortes reinforced his army with new men and supplies, deepened his alliance with the Tlaxcalan state, and constructed a fleet of brigantines to control the lake surrounding Tenochtitlan. When he returned in 1521, it was not as a fugitive but as the leader of a siege that would last 75 days and end with the fall of the Aztec capital and the establishment of New Spain. For the Mexica, Otumba represented a missed opportunity to destroy the invaders while they were vulnerable. For the Spanish, it was the battle that kept the conquest alive -- won not by superior numbers or technology, but by a single cavalry charge aimed at one man carrying a flag.
Located at 19.70N, 98.75W on the plain near Otumba (modern Otumba de Gomez Farias) in the State of Mexico, approximately 45 km northeast of Mexico City. The terrain is a broad, relatively flat valley -- the kind of ground that would have favored cavalry. The site sits between Teotihuacan to the northwest and the route toward Tlaxcala to the east. Mexico City International Airport (ICAO: MMMX) is the nearest major facility. Elevation approximately 2,350 meters.