Answer:
Cortes was able to rally the vassals of Aztecs against their overlords
Step-by-step explanation:
Aztecs were a rough overlord for the kingdoms they conquered. As conquistadors sent their expeditionary force, they were able to rally a revolt against the Aztec force and crush their main forces with superiority in tactics, equipment unseen before by the Aztecs (guns, horses, plate armor) and help of their numerous allies who helped provide manpower and knowledge of the area