Final answer:
Hernán Cortés's victory over the Aztecs was aided by alliances with indigenous groups, the introduction of smallpox, and the diplomatic contributions of Doña Marina. Disunity within the Aztec Empire also facilitated the Spanish conquest.
Step-by-step explanation:
Beyond his strategy and weaponry, what helped Hernán Cortés defeat the Aztecs were several key factors. Significantly, the disunity among the diverse groups within the Aztec Empire played a pivotal role in the Spanish conquest. The formation of alliances with indigenous peoples, such as the Tlaxcalans, who were subjugated by or resentful of Aztec rule, provided Cortés with additional military forces. Moreover, the introduction of smallpox and other diseases by the Europeans devastated the native population, as they had no immunity to these new illnesses. Also, the capture and use of Moctezuma as a hostage and eventually his death further destabilized Aztec society. Furthermore, the translation and diplomatic services of Doña Marina, also known as La Malinche, were instrumental in facilitating communication and alliances with various native groups.