Conversation so far:
When did the colonization of Mexico begin?
The Spanish conquest of Mexico is generally understood to be the Spanish conquest of the Aztec Empire (1519-21) which was the base for later conquests of other regions.
What happened during this period?
Later conquests were protracted campaigns with less spectacular results than the conquest of the Aztecs.
What was so spectacular about the conquest of the Aztecs?
The victory over the Aztecs was relatively quick, from 1519 to 1521, and aided by his Tlaxcala and other allies from indigenous city-states or altepetl.

Question: What else happened during this time?
Self-contained rewrite: Besides the conquest of the Aztecs, what else happened during 1519-21?