- Superior weaponry: The Spanish had access to guns, which were much more powerful than the bows and arrows used by the Native Americans. They also had steel armor, which protected them from the Native Americans' weapons.
- Horses: The Spanish were the first Europeans to introduce horses to the Americas. Horses gave the Spanish a significant advantage in mobility, allowing them to travel quickly and cover long distances.
- Alliances with Native American groups: The Spanish were able to form alliances with some Native American groups, who were unhappy with the rule of the Aztec Empire. These alliances provided the Spanish with additional troops and support.
- Disease: The Spanish brought diseases with them to the Americas, such as smallpox and measles, which devastated the Native American population.