Aztec Empire smallpox epidemic
The Aztec Empire smallpox epidemic occurred between 1520 and 1521 and played a pivotal role in the Spanish conquest of the Aztec civilization. The outbreak began when a soldier carrying the virus traveled with Hernán Cortés's expedition, leading to rapid transmission among the indigenous population, who had no prior exposure or immunity to the disease. The epidemic struck at a crucial moment, as the Aztecs were already resisting Spanish forces, resulting in devastating fatalities estimated to be between one-third and one-half of the population. This high mortality rate severely weakened the social structure, leadership, and military capability of the Aztecs, contributing to their inability to repel the Spaniards effectively.
The smallpox outbreak had far-reaching consequences, exacerbating the chaos and suffering within Tenochtitlán, with entire families succumbing to the disease and leaving homes abandoned. Historical accounts vary regarding the extent of the epidemic's impact on the conquest, but it is widely recognized as a major factor that undermined the Aztec resistance. This event highlights the tragic intersection of European colonization and indigenous vulnerability to diseases, significantly altering the course of history in Mesoamerica.
On this Page
Aztec Empire smallpox epidemic
Epidemic
Date: 1520-1521
Place: Tenochtitlán, Aztec Empire
Result: 2 to 5 million dead
Spanish conquest and colonization of Mexico began in 1519 when Hernán Cortés was ordered by Diego Velázquez, governor of Cuba, to command an expedition to the mainland of Mesoamerica. The smallpox epidemic of 1520-1521 figured importantly in the unlikely conquest of an empire of millions by a much smaller force of Spaniards accompanied by their Native American allies. Landing on the Yucatán peninsula, Cortés marched inland, collecting allies en route to the capital of the Aztec Empire, Tenochtitlán, where he took the emperor, Moctezuma II, prisoner. In 1520, Cortés left Tenochtitlán, leaving some of his men behind to hold the city, in order to meet an expedition on the coast sent by Velázquez, who suspected the ambitious Cortés of exceeding his orders. Cortés convinced these forces to join him rather than arrest him, and he returned to Tenochtitlán. He found a capital where the Indians were in the throes of rebellion against the Spanish. In June of 1520 the Aztecs succeeded in repelling the Spanish. Few Spaniards survived la noche triste (the sad night). Cortés and the remainder of his troops retreated to Tlaxcala to rebuild his fighting forces.
Meanwhile, a smallpox epidemic was proceeding from Yucatán to Tenochtitlán. A soldier who had an active case of smallpox came with the expedition to arrest Cortés. According to some chroniclers his name was Francisco Eguia. He infected Indians with the viral disease, and it was quickly spread from person to person and from village to village, progressing rapidly from the coast to the interior. The disease was reported to have arrived in April or May of 1520; it spread inland from May to September, and it reached Tenochtitlán in September or October.
The effects of the outbreak in America were far greater than were experienced during an outbreak in Europe during the same period. The susceptibility of the American Indians compared to the Spanish can be accounted for by the fact that this disease was unknown to them. The Aztecs had no specific word in their language for smallpox and usually described it in their writings by its characteristic pustules. In Europe the disease had been extant for centuries, and when it reappeared there were usually many persons who were immune because of previous exposure. In contrast, the Indian population was extremely vulnerable to the disease. There were no immune persons in the population, and the people were highly homogeneous genetically, which meant that the virus did not have to adapt to various genetic makeups to be successful in infecting the host. In addition, the first outbreak of a disease within a group is generally the most severe.
This disease wreaked disaster on the indigenous population. It is estimated that one-third to one-half of the population died during the epidemic. In contrast, only about 10 percent of a European population died in an outbreak in the sixteenth century. Because all segments of the population in America were vulnerable, there were few healthy caregivers to sustain the sick. In addition, many rulers were struck down. In Cortés’s letters to the king, he reported that he was asked by many Indian groups who were allied with him against the Aztecs to choose a leader to replace someone who had died of smallpox.
Most important, the epidemic reached Tenochtitlán at a crucial moment in history. The Aztecs had forced Cortés to retreat, but during his time of rest and rebuilding he sent spies into Tenochtitlán to determine the strength of his opponents. He learned that the Aztecs had been struck down with smallpox and were greatly weakened. At times, the disease struck so many persons that no one in a family was able to give care to the others, and whole families died, not only of smallpox but also of thirst and starvation. Homes were destroyed with the corpses inside to diminish the fetid odor wafting through the once-great city. Bodies were thrown into the water, offering a wretched sight of bloated, bobbing flesh. Warriors who survived were weakened by the disease, and their chain of command was compromised. The emperor named to replace Moctezuma died of smallpox. The loss of continuity and experience in leadership greatly weakened the ability of the Aztecs to mount a defense against the Spaniards.
Having replenished his forces, Cortés struck Tenochtitlán again in May of 1521, and within months he had conquered the seat of the Aztec Empire. Debate continues over the role of the smallpox epidemic in this conquest. Cortés did not give it much weight in his chronicles, but Indian chronicles of the time emphasize its importance. The year 1520 is called the year of the pustules, according to Aztec chronicles. Though there is great disagreement among historians over the number of deaths and the importance of the smallpox epidemic in the conquest, there is no doubt that this epidemic was one of the most serious disasters in Mexico in the sixteenth century.
Bibliography
Crosby, Alfred, Jr. The Columbian Exchange: Biological and Cultural Consequences of 1492. Westport, Conn.: Greenwood Press, 1972.
Diamond, Jared. Guns, Germs, and Steel: The Fates of Human Societies. New York: W. W. Norton, 1997.
Glynn, Ian, and Jenifer Glynn. The Life and Death of Smallpox. New York: Cambridge University Press, 2004.
McCaa, Robert. “Spanish and Nahuatl Views on Smallpox and Demographic Catastrophe in Mexico.” The Journal of Interdisciplinary History 25 (Winter, 1995): 397-432.
Noble, David Cook. Born to Die: Disease and New World Conquest, 1492-1650. Cambridge, England: Cambridge University Press, 1998.