What caused the downfall in population in the Aztec empire ?
Aztec smallpox causes
The big disease
Disease it played a huge part in the downfall of the Aztec population. This is what really happened. After Cortes had landed in Mexico, one of the other Spanish armies came from Cuba to make sure Cortes followed the orders that were given him. Cortes would do none of that, and went to fight them. In this new group was an African being held as a slave who had a very dangerous disease called smallpox, now known as Variola.