Cortés’ gang were up against a huge, wealthy and heavily militarized polity that some historians have compared to ancient Sparta. And yet, in one of the most improbable feats of conquest in history, a little over two years after landing in Central America they managed to kill Montezuma, raze his capital and found the colony of New Spain.
It's amazing how 500 men could conquer an empire. I belive however, Cortes did recieve reinforcements after another party was sent to arrest him. Moreover, he had help from other city states opposed to the Mexica. They bolstered his military force and helped Cortes navigate the political environment in that region.
