The Aztec soon grew sick of their guests. Conflict between the two groups erupted into bitter warfare that lasted two years.
Each side had its strengths. The Aztec hugely outnumbered the Spanish and were fighting on familiar ground. But Cortés’s soldiers had steel swords, cannons, and guns—weapons unknown to the Aztec. And they had an accidental ally. Soon, the Aztec Empire would be up for grabs.