Historians once marveled at how Cortés, with his army of five hundred soldiers, defeated the Aztec empire of over a million people. Various ideas have been advanced: that the Spanish had crucial technological advantages in horses, swords, crossbows, cannon, and armor; that the Spanish had superior tactics honed by centuries of fighting the Moors; that the Indians held back, fearful the Spanish were gods; and that the Aztecs’ subjugation and misrule of surrounding chiefdoms had created conditions ripe for revolt. All this is true. But the real conquistador was smallpox.
