The Conquest of Tenochtitlan, 1519-1521
The conquest of the Aztecs by a small band of conquistadores, led by Hernan Cortes, is another example of a very small army that defeated a much larger one. The Cortes expedition set out in February 1519. Accounts vary of the intention of his expedition—the Spanish governor of the region may well have intended only trade and exploration; however, Cortes had distinctly different ideas.
When Cortes reached the Yucatan Peninsula, he began working to form alliances. Cortes had the support of many local tribes who opposed the power of the Aztecs and welcomed the Spanish. The war with the Aztecs began with a confrontation with Aztec forces at Cholula, resisting the oncoming Spanish. Cortes, accompanied by a small number of additional troops, successfully massacred many of the citizens of Cholula, including the nobility.
On November 8, 1519, Cortes and his forces reached the Aztec city of Tenochtitlan, and were initially welcomed. The city of Tenochtitlan was, by the standards of the time, massive; records suggest that the population numbered between 60,000 and 300,000 people. Fairly quickly, Cortes took the Aztec emperor, Moctezuma, prisoner, while enabling him to continue to rule.
By the summer of 1520, the conflict between the two parties had escalated. A force of only 3,000 Spanish and native warriors eventually took the city of Tenochtitlan, aided by a plague of smallpox that decimated the population of the city.