Westerners have a tendency to idolize the pre-history of American civilization, painting the native Americans as a relatively peaceful, if technologically backwards people. An exhibit at the British Museum, however, disputes that interpretation. In an exhibit about the Aztecs just before Cortés' arrival on the continent, the horrors of the Aztec's merciless killing machine are described:
When the recently excavated pyramid whose finds provide the centrepiece of the British Museum show was first inaugurated in 1484, there were prisoners lined up for sacrifice stretching in all directions as far as the eye could see. Some estimate that 20,000 victims were killed over four days.
The author draws an analogy between the Aztecs' reign with that of the Nazis – both expanded quickly on the backs of vast killing machines, but were short lived, as the conquest-by-terror method is not sustainable in the long term. According to a book by Hugh Thompson, many tribes conquered by the Aztecs colluded with the Spanish against the Aztec king Moctezuma.
But the most interesting part is the historiography of the noble Aztecs and horrible Spanish. Apparently the trope began as English propaganda against the then-formidable Spanish empire:
So why is he remembered by history as “a gentle prince”? The English had a hand in this: the conquest of the New World by Spain made it the European superpower and helped to finance the Armada. Hardly surprising that English propaganda should seize every opportunity to play up the leyenda negra, “the black legend” of Spanish cruelty in Mexico, and portray Moctezuma (and later Atahualpa in Peru) as hapless victims.
I'm not sure that this is entirely true – the idea of the "noble savage" is universal in modern Western civilization and not at all specific to what was once New Spain. But it's interesting to think about how centuries old imperial rivalries affect the way we think of history today.